# SQLAlchemy 0.8 Documentation

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Release: 0.8.2 | Release Date: July 3, 2013

# SQL Statements and Expressions API

This section presents the API reference for the SQL Expression Language. For a full introduction to its usage, see SQL Expression Language Tutorial.

## Functions

The expression package uses functions to construct SQL expressions. The return value of each function is an object instance which is a subclass of `ClauseElement`.

`sqlalchemy.sql.expression.``alias`(selectable, name=None)

  Return an `Alias` object.

  An `Alias` represents any `FromClause` with an alternate name assigned within SQL, typically using the `AS` clause when generated, e.g. `SELECT * FROM table AS aliasname`.

  Similar functionality is available via the `alias()` method available on all `FromClause` subclasses.

  When an `Alias` is created from a `Table` object, this has the effect of the table being rendered as `tablename AS aliasname` in a SELECT statement.

  For `select()` objects, the effect is that of creating a named subquery, i.e. `(select ...) AS aliasname`.

  The `name` parameter is optional, and provides the name to use in the rendered SQL. If blank, an “anonymous” name will be deterministically generated at compile time. Deterministic means the name is guaranteed to be unique against other constructs used in the same statement, and will also be the same name for each successive compilation of the same statement object.

  Parameters: | selectable – any `FromClause` subclass, such as a table, select statement, etc. name – string name to be assigned as the alias. If `None`, a name will be deterministically generated at compile time.

`sqlalchemy.sql.expression.``and_`(*clauses)

  Join a list of clauses together using the `AND` operator.

  The `&` operator is also overloaded on all `ColumnElement` subclasses to produce the same result.

`sqlalchemy.sql.expression.``asc`(column)

  Return an ascending `ORDER BY` clause element.

  e.g.:

      someselect.order_by(asc(table1.mycol))

  produces:

      ORDER BY mycol ASC

`sqlalchemy.sql.expression.``between`(ctest, cleft, cright)

  Return a `BETWEEN` predicate clause.

  Equivalent of SQL `clausetest BETWEEN clauseleft AND clauseright`.

  The `between()` method on all `ColumnElement` subclasses provides similar functionality.

`sqlalchemy.sql.expression.``bindparam`(key, value=<symbol 'NO_ARG>, type_=None, unique=False, required=<symbol 'NO_ARG>, quote=None, callable_=None)

  Create a bind parameter clause with the given key.

  Parameters: | key – the key for this bind param. Will be used in the generated SQL statement for dialects that use named parameters. This value may be modified when part of a compilation operation, if other `BindParameter` objects exist with the same key, or if its length is too long and truncation is required. value – Initial value for this bind param. This value may be overridden by the dictionary of parameters sent to statement compilation/execution. Defaults to `None`, however if neither `value` nor `callable` are passed explicitly, the `required` flag will be set to `True` which has the effect of requiring a value be present when the statement is actually executed. Changed in version 0.8: The `required` flag is set to `True` automatically if `value` or `callable` is not passed. callable_ – A callable function that takes the place of “value”. The function will be called at statement execution time to determine the ultimate value. Used for scenarios where the actual bind value cannot be determined at the point at which the clause construct is created, but embedded bind values are still desirable. type_ – A `TypeEngine` object that will be used to pre-process the value corresponding to this `BindParameter` at execution time. unique – if True, the key name of this BindParamClause will be modified if another `BindParameter` of the same name already has been located within the containing `ClauseElement`. required – If `True`, a value is required at execution time. If not passed, is set to `True` or `False` based on whether or not one of `value` or `callable` were passed.. Changed in version 0.8: If the `required` flag is not specified, it will be set automatically to `True` or `False` depending on whether or not the `value` or `callable` parameters were specified. quote – True if this parameter name requires quoting and is not currently known as a SQLAlchemy reserved word; this currently only applies to the Oracle backend.

`sqlalchemy.sql.expression.``case`(whens, value=None, else_=None)

  Produce a `CASE` statement.

  whens
    A sequence of pairs, or alternatively a dict, to be translated into “WHEN / THEN” clauses.
  value
    Optional for simple case statements, produces a column expression as in “CASE <expr> WHEN ...”
  else_
    Optional as well, for case defaults produces the “ELSE” portion of the “CASE” statement.

  The expressions used for THEN and ELSE, when specified as strings, will be interpreted as bound values. To specify textual SQL expressions for these, use the `literal_column()` construct.

  The expressions used for the WHEN criterion may only be literal strings when “value” is present, i.e. CASE table.somecol WHEN “x” THEN “y”. Otherwise, literal strings are not accepted in this position, and either the text(<string>) or literal(<string>) constructs must be used to interpret raw string values.

  Usage examples:

      case([(orderline.c.qty > 100, item.c.specialprice),
            (orderline.c.qty > 10, item.c.bulkprice)
          ], else_=item.c.regularprice)
      case(value=emp.c.type, whens={
              'engineer': emp.c.salary * 1.1,
              'manager':  emp.c.salary * 3,
          })

  Using `literal_column()`, to allow for databases that do not support bind parameters in the `then` clause. The type can be specified which determines the type of the `case()` construct overall:

      case([(orderline.c.qty > 100,
              literal_column("'greaterthan100'", String)),
            (orderline.c.qty > 10, literal_column("'greaterthan10'",
              String))
          ], else_=literal_column("'lethan10'", String))

`sqlalchemy.sql.expression.``cast`(clause, totype, **kwargs)

  Return a `CAST` function.

  Equivalent of SQL `CAST(clause AS totype)`.

  Use with a `TypeEngine` subclass, i.e:

      cast(table.c.unit_price * table.c.qty, Numeric(10,4))

  or:

      cast(table.c.timestamp, DATE)

`sqlalchemy.sql.expression.``column`(text, type_=None)

  Return a textual column clause, as would be in the columns clause of a `SELECT` statement.

  The object returned is an instance of `ColumnClause`, which represents the “syntactical” portion of the schema-level `Column` object. It is often used directly within `select()` constructs or with lightweight `table()` constructs.

  Note that the `column()` function is not part of the `sqlalchemy` namespace. It must be imported from the `sql` package:

      from sqlalchemy.sql import table, column

  Parameters: | text – the name of the column. Quoting rules will be applied to the clause like any other column name. For textual column constructs that are not to be quoted, use the `literal_column()` function. type_ – an optional `TypeEngine` object which will provide result-set translation for this column.

  See `ColumnClause` for further examples.

`sqlalchemy.sql.expression.``collate`(expression, collation)

  Return the clause `expression COLLATE collation`.

  e.g.:

      collate(mycolumn, 'utf8_bin')

  produces:

      mycolumn COLLATE utf8_bin

`sqlalchemy.sql.expression.``delete`(table, whereclause=None, **kwargs)

  Represent a `DELETE` statement via the `Delete` SQL construct.

  Similar functionality is available via the `delete()` method on `Table`.

  Parameters: | table – The table to be updated. whereclause – A `ClauseElement` describing the `WHERE` condition of the `UPDATE` statement. Note that the `where()` generative method may be used instead.

  See also

  Deletes - SQL Expression Tutorial

`sqlalchemy.sql.expression.``desc`(column)

  Return a descending `ORDER BY` clause element.

  e.g.:

      someselect.order_by(desc(table1.mycol))

  produces:

      ORDER BY mycol DESC

`sqlalchemy.sql.expression.``distinct`(expr)

  Return a `DISTINCT` clause.

  e.g.:

      distinct(a)

  renders:

      DISTINCT a

`sqlalchemy.sql.expression.``except_`(*selects, **kwargs)

  Return an `EXCEPT` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.``except_all`(*selects, **kwargs)

  Return an `EXCEPT ALL` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.``exists`(*args, **kwargs)

  Return an `EXISTS` clause as applied to a `Select` object.

  Calling styles are of the following forms:

      # use on an existing select()
      s = select([table.c.col1]).where(table.c.col2==5)
      s = exists(s)

      # construct a select() at once
      exists(['*'], **select_arguments).where(criterion)

      # columns argument is optional, generates "EXISTS (SELECT *)"
      # by default.
      exists().where(table.c.col2==5)

`sqlalchemy.sql.expression.``extract`(field, expr)

  Return the clause `extract(field FROM expr)`.

`sqlalchemy.sql.expression.``false`()

  Return a `False_` object, which compiles to `false`, or the boolean equivalent for the target dialect.

`sqlalchemy.sql.expression.``func` = <sqlalchemy.sql.expression._FunctionGenerator object at 0x1019b9b10>

  Generate SQL function expressions.

  `func` is a special object instance which generates SQL functions based on name-based attributes, e.g.:

      >>> print func.count(1)
      count(:param_1)

  The element is a column-oriented SQL element like any other, and is used in that way:

      >>> print select([func.count(table.c.id)])
      SELECT count(sometable.id) FROM sometable

  Any name can be given to `func`. If the function name is unknown to SQLAlchemy, it will be rendered exactly as is. For common SQL functions which SQLAlchemy is aware of, the name may be interpreted as a generic function which will be compiled appropriately to the target database:

      >>> print func.current_timestamp()
      CURRENT_TIMESTAMP

  To call functions which are present in dot-separated packages, specify them in the same manner:

      >>> print func.stats.yield_curve(5, 10)
      stats.yield_curve(:yield_curve_1, :yield_curve_2)

  SQLAlchemy can be made aware of the return type of functions to enable type-specific lexical and result-based behavior. For example, to ensure that a string-based function returns a Unicode value and is similarly treated as a string in expressions, specify `Unicode` as the type:

      >>> print func.my_string(u'hi', type_=Unicode) + ' ' + \
      ... func.my_string(u'there', type_=Unicode)
      my_string(:my_string_1) || :my_string_2 || my_string(:my_string_3)

  The object returned by a `func` call is usually an instance of `Function`. This object meets the “column” interface, including comparison and labeling functions. The object can also be passed the `execute()` method of a `Connection` or `Engine`, where it will be wrapped inside of a SELECT statement first:

      print connection.execute(func.current_timestamp()).scalar()

  In a few exception cases, the `func` accessor will redirect a name to a built-in expression such as `cast()` or `extract()`, as these names have well-known meaning but are not exactly the same as “functions” from a SQLAlchemy perspective.

  New in version 0.8: `func` can return non-function expression constructs for common quasi-functional names like `cast()` and `extract()`.

  Functions which are interpreted as “generic” functions know how to calculate their return type automatically. For a listing of known generic functions, see Generic Functions.

`sqlalchemy.sql.expression.``insert`(table, values=None, inline=False, **kwargs)

  Represent an `INSERT` statement via the `Insert` SQL construct.

  Similar functionality is available via the `insert()` method on `Table`.

  Parameters: | table – `TableClause` which is the subject of the insert. values – collection of values to be inserted; see `Insert.values()` for a description of allowed formats here. Can be omitted entirely; a `Insert` construct will also dynamically render the VALUES clause at execution time based on the parameters passed to `Connection.execute()`. inline – if True, SQL defaults will be compiled ‘inline’ into the statement and not pre-executed.

  If both values and compile-time bind parameters are present, the compile-time bind parameters override the information specified within values on a per-key basis.

  The keys within values can be either `Column` objects or their string identifiers. Each key may reference one of:

  - a literal data value (i.e. string, number, etc.);
  - a Column object;
  - a SELECT statement.

  If a `SELECT` statement is specified which references this `INSERT` statement’s table, the statement will be correlated against the `INSERT` statement.

  See also

  Insert Expressions - SQL Expression Tutorial

  Inserts, Updates and Deletes - SQL Expression Tutorial

`sqlalchemy.sql.expression.``intersect`(*selects, **kwargs)

  Return an `INTERSECT` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.``intersect_all`(*selects, **kwargs)

  Return an `INTERSECT ALL` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.``join`(left, right, onclause=None, isouter=False)

  Return a `JOIN` clause element (regular inner join).

  The returned object is an instance of `Join`.

  Similar functionality is also available via the `join()` method on any `FromClause`.

  Parameters: | left – The left side of the join. right – The right side of the join. onclause – Optional criterion for the `ON` clause, is derived from foreign key relationships established between left and right otherwise.

  To chain joins together, use the `FromClause.join()` or `FromClause.outerjoin()` methods on the resulting `Join` object.

`sqlalchemy.sql.expression.``label`(name, obj)

  Return a `Label` object for the given `ColumnElement`.

  A label changes the name of an element in the columns clause of a `SELECT` statement, typically via the `AS` SQL keyword.

  This functionality is more conveniently available via the `label()` method on `ColumnElement`.

  name
    label name
  obj
    a `ColumnElement`.

`sqlalchemy.sql.expression.``literal`(value, type_=None)

  Return a literal clause, bound to a bind parameter.

  Literal clauses are created automatically when non- `ClauseElement` objects (such as strings, ints, dates, etc.) are used in a comparison operation with a `ColumnElement` subclass, such as a `Column` object. Use this function to force the generation of a literal clause, which will be created as a `BindParameter` with a bound value.

  Parameters: | value – the value to be bound. Can be any Python object supported by the underlying DB-API, or is translatable via the given type argument. type_ – an optional `TypeEngine` which will provide bind-parameter translation for this literal.

`sqlalchemy.sql.expression.``literal_column`(text, type_=None)

  Return a textual column expression, as would be in the columns clause of a `SELECT` statement.

  The object returned supports further expressions in the same way as any other column object, including comparison, math and string operations. The type_ parameter is important to determine proper expression behavior (such as, ‘+’ means string concatenation or numerical addition based on the type).

  Parameters: | text – the text of the expression; can be any SQL expression. Quoting rules will not be applied. To specify a column-name expression which should be subject to quoting rules, use the `column()` function. type_ – an optional `TypeEngine` object which will provide result-set translation and additional expression semantics for this column. If left as None the type will be NullType.

`sqlalchemy.sql.expression.``not_`(clause)

  Return a negation of the given clause, i.e. `NOT(clause)`.

  The `~` operator is also overloaded on all `ColumnElement` subclasses to produce the same result.

`sqlalchemy.sql.expression.``null`()

  Return a `Null` object, which compiles to `NULL`.

`sqlalchemy.sql.expression.``nullsfirst`(column)

  Return a NULLS FIRST `ORDER BY` clause element.

  e.g.:

      someselect.order_by(desc(table1.mycol).nullsfirst())

  produces:

      ORDER BY mycol DESC NULLS FIRST

`sqlalchemy.sql.expression.``nullslast`(column)

  Return a NULLS LAST `ORDER BY` clause element.

  e.g.:

      someselect.order_by(desc(table1.mycol).nullslast())

  produces:

      ORDER BY mycol DESC NULLS LAST

`sqlalchemy.sql.expression.``or_`(*clauses)

  Join a list of clauses together using the `OR` operator.

  The `|` operator is also overloaded on all `ColumnElement` subclasses to produce the same result.

`sqlalchemy.sql.expression.``outparam`(key, type_=None)

  Create an ‘OUT’ parameter for usage in functions (stored procedures), for databases which support them.

  The `outparam` can be used like a regular function parameter. The “output” value will be available from the `ResultProxy` object via its `out_parameters` attribute, which returns a dictionary containing the values.

`sqlalchemy.sql.expression.``outerjoin`(left, right, onclause=None)

  Return an `OUTER JOIN` clause element.

  The returned object is an instance of `Join`.

  Similar functionality is also available via the `outerjoin()` method on any `FromClause`.

  Parameters: | left – The left side of the join. right – The right side of the join. onclause – Optional criterion for the `ON` clause, is derived from foreign key relationships established between left and right otherwise.

  To chain joins together, use the `FromClause.join()` or `FromClause.outerjoin()` methods on the resulting `Join` object.

`sqlalchemy.sql.expression.``over`(func, partition_by=None, order_by=None)

  Produce an OVER clause against a function.

  Used against aggregate or so-called “window” functions, for database backends that support window functions.

  E.g.:

      from sqlalchemy import over
      over(func.row_number(), order_by='x')

  Would produce “ROW_NUMBER() OVER(ORDER BY x)”.

  Parameters: | func – a `FunctionElement` construct, typically generated by `func`. partition_by – a column element or string, or a list of such, that will be used as the PARTITION BY clause of the OVER construct. order_by – a column element or string, or a list of such, that will be used as the ORDER BY clause of the OVER construct.

  This function is also available from the `func` construct itself via the `FunctionElement.over()` method.

  New in version 0.7.

`sqlalchemy.sql.expression.``select`(columns=None, whereclause=None, from_obj=[], **kwargs)

  Returns a `SELECT` clause element.

  Similar functionality is also available via the `select()` method on any `FromClause`.

  The returned object is an instance of `Select`.

  All arguments which accept `ClauseElement` arguments also accept string arguments, which will be converted as appropriate into either `text()` or `literal_column()` constructs.

  See also

  Selecting - Core Tutorial description of `select()`.

  Parameters: | columns – A list of `ClauseElement` objects, typically `ColumnElement` objects or subclasses, which will form the columns clause of the resulting statement. For all members which are instances of `Selectable`, the individual `ColumnElement` members of the `Selectable` will be added individually to the columns clause. For example, specifying a `Table` instance will result in all the contained `Column` objects within to be added to the columns clause. This argument is not present on the form of `select()` available on `Table`. whereclause – A `ClauseElement` expression which will be used to form the `WHERE` clause. from_obj – A list of `ClauseElement` objects which will be added to the `FROM` clause of the resulting statement. Note that “from” objects are automatically located within the columns and whereclause ClauseElements. Use this parameter to explicitly specify “from” objects which are not automatically locatable. This could include `Table` objects that aren’t otherwise present, or `Join` objects whose presence will supercede that of the `Table` objects already located in the other clauses. autocommit – Deprecated. Use .execution_options(autocommit=<True|False>) to set the autocommit option. bind=None – an `Engine` or `Connection` instance to which the resulting `Select` object will be bound. The `Select` object will otherwise automatically bind to whatever `Connectable` instances can be located within its contained `ClauseElement` members. correlate=True – indicates that this `Select` object should have its contained `FromClause` elements “correlated” to an enclosing `Select` object. This means that any `ClauseElement` instance within the “froms” collection of this `Select` which is also present in the “froms” collection of an enclosing select will not be rendered in the `FROM` clause of this select statement. distinct=False – when `True`, applies a `DISTINCT` qualifier to the columns clause of the resulting statement. The boolean argument may also be a column expression or list of column expressions - this is a special calling form which is understood by the Postgresql dialect to render the `DISTINCT ON (<columns>)` syntax. `distinct` is also available via the `distinct()` generative method. for_update=False – when `True`, applies `FOR UPDATE` to the end of the resulting statement. Certain database dialects also support alternate values for this parameter: With the MySQL dialect, the value `"read"` translates to `LOCK IN SHARE MODE`. With the Oracle and Postgresql dialects, the value `"nowait"` translates to `FOR UPDATE NOWAIT`. With the Postgresql dialect, the values “read” and `"read_nowait"` translate to `FOR SHARE` and `FOR SHARE NOWAIT`, respectively. New in version 0.7.7. group_by – a list of `ClauseElement` objects which will comprise the `GROUP BY` clause of the resulting select. having – a `ClauseElement` that will comprise the `HAVING` clause of the resulting select when `GROUP BY` is used. limit=None – a numerical value which usually compiles to a `LIMIT` expression in the resulting select. Databases that don’t support `LIMIT` will attempt to provide similar functionality. offset=None – a numeric value which usually compiles to an `OFFSET` expression in the resulting select. Databases that don’t support `OFFSET` will attempt to provide similar functionality. order_by – a scalar or list of `ClauseElement` objects which will comprise the `ORDER BY` clause of the resulting select. use_labels=False – when `True`, the statement will be generated using labels for each column in the columns clause, which qualify each column with its parent table’s (or aliases) name so that name conflicts between columns in different tables don’t occur. The format of the label is <tablename>_<column>. The “c” collection of the resulting `Select` object will use these names as well for targeting column members. use_labels is also available via the `apply_labels()` generative method.

`sqlalchemy.sql.expression.``subquery`(alias, *args, **kwargs)

  Return an `Alias` object derived from a `Select`.

  name
    alias name

  *args, **kwargs

  > all other arguments are delivered to the `select()` function.

`sqlalchemy.sql.expression.``table`(name, *columns)

  Represent a textual table clause.

  The object returned is an instance of `TableClause`, which represents the “syntactical” portion of the schema-level `Table` object. It may be used to construct lightweight table constructs.

  Note that the `table()` function is not part of the `sqlalchemy` namespace. It must be imported from the `sql` package:

      from sqlalchemy.sql import table, column

  Parameters: | name – Name of the table. columns – A collection of `column()` constructs.

  See `TableClause` for further examples.

`sqlalchemy.sql.expression.``text`(text, bind=None, *args, **kwargs)

  Create a SQL construct that is represented by a literal string.

  E.g.:

      t = text("SELECT * FROM users")
      result = connection.execute(t)

  The advantages `text()` provides over a plain string are backend-neutral support for bind parameters, per-statement execution options, as well as bind parameter and result-column typing behavior, allowing SQLAlchemy type constructs to play a role when executing a statement that is specified literally.

  Bind parameters are specified by name, using the format `:name`. E.g.:

      t = text("SELECT * FROM users WHERE id=:user_id")
      result = connection.execute(t, user_id=12)

  To invoke SQLAlchemy typing logic for bind parameters, the `bindparams` list allows specification of `bindparam()` constructs which specify the type for a given name:

      t = text("SELECT id FROM users WHERE updated_at>:updated",
                  bindparams=[bindparam('updated', DateTime())]
              )

  Typing during result row processing is also an important concern. Result column types are specified using the `typemap` dictionary, where the keys match the names of columns. These names are taken from what the DBAPI returns as `cursor.description`:

      t = text("SELECT id, name FROM users",
              typemap={
                  'id':Integer,
                  'name':Unicode
              }
      )

  The `text()` construct is used internally for most cases when a literal string is specified for part of a larger query, such as within `select()`, `update()`, `insert()` or `delete()`. In those cases, the same bind parameter syntax is applied:

      s = select([users.c.id, users.c.name]).where("id=:user_id")
      result = connection.execute(s, user_id=12)

  Using `text()` explicitly usually implies the construction of a full, standalone statement. As such, SQLAlchemy refers to it as an `Executable` object, and it supports the `Executable.execution_options()` method. For example, a `text()` construct that should be subject to “autocommit” can be set explicitly so using the `autocommit` option:

      t = text("EXEC my_procedural_thing()").\
              execution_options(autocommit=True)

  Note that SQLAlchemy’s usual “autocommit” behavior applies to `text()` constructs - that is, statements which begin with a phrase such as `INSERT`, `UPDATE`, `DELETE`, or a variety of other phrases specific to certain backends, will be eligible for autocommit if no transaction is in progress.

  Parameters: | text – the text of the SQL statement to be created. use `:<param>` to specify bind parameters; they will be compiled to their engine-specific format. autocommit – Deprecated. Use .execution_options(autocommit=<True|False>) to set the autocommit option. bind – an optional connection or engine to be used for this text query. bindparams – a list of `bindparam()` instances which can be used to define the types and/or initial values for the bind parameters within the textual statement; the keynames of the bindparams must match those within the text of the statement. The types will be used for pre-processing on bind values. typemap – a dictionary mapping the names of columns represented in the columns clause of a `SELECT` statement to type objects, which will be used to perform post-processing on columns within the result set. This argument applies to any expression that returns result sets.

`sqlalchemy.sql.expression.``true`()

  Return a `True_` object, which compiles to `true`, or the boolean equivalent for the target dialect.

`sqlalchemy.sql.expression.``tuple_`(*expr)

  Return a SQL tuple.

  Main usage is to produce a composite IN construct:

      tuple_(table.c.col1, table.c.col2).in_(
          [(1, 2), (5, 12), (10, 19)]
      )

  Warning

  The composite IN construct is not supported by all backends, and is currently known to work on Postgresql and MySQL, but not SQLite. Unsupported backends will raise a subclass of `DBAPIError` when such an expression is invoked.

`sqlalchemy.sql.expression.``type_coerce`(expr, type_)

  Coerce the given expression into the given type, on the Python side only.

  `type_coerce()` is roughly similar to `cast()`, except no “CAST” expression is rendered - the given type is only applied towards expression typing and against received result values.

  e.g.:

      from sqlalchemy.types import TypeDecorator
      import uuid

      class AsGuid(TypeDecorator):
          impl = String

          def process_bind_param(self, value, dialect):
              if value is not None:
                  return str(value)
              else:
                  return None

          def process_result_value(self, value, dialect):
              if value is not None:
                  return uuid.UUID(value)
              else:
                  return None

      conn.execute(
          select([type_coerce(mytable.c.ident, AsGuid)]).\
                  where(
                      type_coerce(mytable.c.ident, AsGuid) ==
                      uuid.uuid3(uuid.NAMESPACE_URL, 'bar')
                  )
      )

`sqlalchemy.sql.expression.``union`(*selects, **kwargs)

  Return a `UNION` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  A similar `union()` method is available on all `FromClause` subclasses.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.``union_all`(*selects, **kwargs)

  Return a `UNION ALL` of multiple selectables.

  The returned object is an instance of `CompoundSelect`.

  A similar `union_all()` method is available on all `FromClause` subclasses.

  *selects
    a list of `Select` instances.
  **kwargs
    available keyword arguments are the same as those of `select()`.

`sqlalchemy.sql.expression.``update`(table, whereclause=None, values=None, inline=False, **kwargs)

  Represent an `UPDATE` statement via the `Update` SQL construct.

  E.g.:

      from sqlalchemy import update

      stmt = update(users).where(users.c.id==5).\
              values(name='user #5')

  Similar functionality is available via the `update()` method on `Table`:

      stmt = users.update().\
                  where(users.c.id==5).\
                  values(name='user #5')

  - Parameters: | table – A `Table` object representing the database table to be updated. whereclause – Optional SQL expression describing the `WHERE` condition of the `UPDATE` statement. Modern applications may prefer to use the generative `where()` method to specify the `WHERE` clause. The WHERE clause can refer to multiple tables. For databases which support this, an `UPDATE FROM` clause will be generated, or on MySQL, a multi-table update. The statement will fail on databases that don’t have support for multi-table update statements. A SQL-standard method of referring to additional tables in the WHERE clause is to use a correlated subquery:
        users.update().values(name='ed').where(
                users.c.name==select([addresses.c.email_address]).\
                            where(addresses.c.user_id==users.c.id).\
                            as_scalar()
                )
  Changed in version 0.7.4: The WHERE clause can refer to multiple tables. values – Optional dictionary which specifies the `SET` conditions of the `UPDATE`. If left as `None`, the `SET` conditions are determined from those parameters passed to the statement during the execution and/or compilation of the statement. When compiled standalone without any parameters, the `SET` clause generates for all columns. Modern applications may prefer to use the generative `Update.values()` method to set the values of the UPDATE statement. inline – if True, SQL defaults present on `Column` objects via the `default` keyword will be compiled ‘inline’ into the statement and not pre-executed. This means that their values will not be available in the dictionary returned from `ResultProxy.last_updated_params()`.

  If both `values` and compile-time bind parameters are present, the compile-time bind parameters override the information specified within `values` on a per-key basis.

  The keys within `values` can be either `Column` objects or their string identifiers (specifically the “key” of the `Column`, normally but not necessarily equivalent to its “name”). Normally, the `Column` objects used here are expected to be part of the target `Table` that is the table to be updated. However when using MySQL, a multiple-table UPDATE statement can refer to columns from any of the tables referred to in the WHERE clause.

  The values referred to in `values` are typically:

  - a literal data value (i.e. string, number, etc.)
  - a SQL expression, such as a related `Column`, a scalar-returning `select()` construct, etc.

  When combining `select()` constructs within the values clause of an `update()` construct, the subquery represented by the `select()` should be correlated to the parent table, that is, providing criterion which links the table inside the subquery to the outer table being updated:

      users.update().values(
              name=select([addresses.c.email_address]).\
                      where(addresses.c.user_id==users.c.id).\
                      as_scalar()
          )

  See also

  Inserts, Updates and Deletes - SQL Expression Language Tutorial

## Classes

class `sqlalchemy.sql.expression.``Alias`(selectable, name=None)

  Bases: `sqlalchemy.sql.expression.FromClause`

  Represents an table or selectable alias (AS).

  Represents an alias, as typically applied to any table or sub-select within a SQL statement using the `AS` keyword (or without the keyword on certain databases such as Oracle).

  This object is constructed from the `alias()` module level function as well as the `FromClause.alias()` method available on all `FromClause` subclasses.

  `alias`(name=None)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `join`(right, onclause=None, isouter=False)
    inherited from the `join()` method of `FromClause`

    return a join of this `FromClause` against another `FromClause`.

  `outerjoin`(right, onclause=None)
    inherited from the `outerjoin()` method of `FromClause`

    return an outer join of this `FromClause` against another `FromClause`.

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.``BinaryExpression`(left, right, operator, type_=None, negate=None, modifiers=None)

  Bases: `sqlalchemy.sql.expression.ColumnElement`

  Represent an expression that is `LEFT <operator> RIGHT`.

  A `BinaryExpression` is generated automatically whenever two column expressions are used in a Python binary expresion:

      >>> from sqlalchemy.sql import column
      >>> column('a') + column('b')
      <sqlalchemy.sql.expression.BinaryExpression object at 0x101029dd0>
      >>> print column('a') + column('b')
      a + b

  `__eq__`(other)
    inherited from the `__eq__()` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__le__`(other)
    inherited from the `__le__()` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lt__`(other)
    inherited from the `__lt__()` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__ne__`(other)
    inherited from the `__ne__()` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `anon_label`
    inherited from the `anon_label` attribute of `ColumnElement`

    provides a constant ‘anonymous label’ for this ColumnElement.

    This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.

    the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.

  `asc`()
    inherited from the `asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright)
    inherited from the `between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `collate`(collation)
    inherited from the `collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

  `compare`(other, **kw)

    Compare this `BinaryExpression` against the given `BinaryExpression`.

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `concat`(other)
    inherited from the `concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)
    inherited from the `contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    In a column context, produces the clause `LIKE '%<other>%'`

  `desc`()
    inherited from the `desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  `distinct`()
    inherited from the `distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  `endswith`(other, **kwargs)
    inherited from the `endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    In a column context, produces the clause `LIKE '%<other>'`

  `expression`
    inherited from the `expression` attribute of `ColumnElement`

    Return a column expression.

    Part of the inspection interface; returns self.

  `ilike`(other, escape=None)
    inherited from the `ilike()` method of `ColumnOperators`

    Implement the `ilike` operator.

    In a column context, produces the clause `a ILIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)
    inherited from the `in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

  `is_`(other)
    inherited from the `is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `isnot`(other)
    inherited from the `isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `label`(name)
    inherited from the `label()` method of `ColumnElement`

    Produce a column label, i.e. `<columnname> AS <name>`.

    This is a shortcut to the `label()` function.

    if ‘name’ is None, an anonymous label name will be generated.

  `like`(other, escape=None)
    inherited from the `like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the clause `a LIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)
    inherited from the `match()` method of `ColumnOperators`

    Implements the ‘match’ operator.

    In a column context, this produces a MATCH clause, i.e. `MATCH '<other>'`. The allowed contents of `other` are database backend specific.

  `notilike`(other, escape=None)
    inherited from the `notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)
    inherited from the `notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)
    inherited from the `notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()
    inherited from the `nullsfirst()` method of `ColumnOperators`

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()
    inherited from the `nullslast()` method of `ColumnOperators`

    Produce a `nullslast()` clause against the parent object.

  `op`(opstring, precedence=0)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument.

    See also

    Redefining and Creating New Operators

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `shares_lineage`(othercolumn)
    inherited from the `shares_lineage()` method of `ColumnElement`

    Return True if the given `ColumnElement` has a common ancestor to this `ColumnElement`.

  `startswith`(other, **kwargs)
    inherited from the `startswith()` method of `ColumnOperators`

    Implement the `startwith` operator.

    In a column context, produces the clause `LIKE '<other>%'`

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.``BindParameter`(key, value, type_=None, unique=False, callable_=None, isoutparam=False, required=False, quote=None, _compared_to_operator=None, _compared_to_type=None)

  Bases: `sqlalchemy.sql.expression.ColumnElement`

  Represent a bind parameter.

  Public constructor is the `bindparam()` function.

  `__eq__`(other)
    inherited from the `__eq__()` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__init__`(key, value, type_=None, unique=False, callable_=None, isoutparam=False, required=False, quote=None, _compared_to_operator=None, _compared_to_type=None)

    Construct a BindParameter.

    Parameters: | key – the key for this bind param. Will be used in the generated SQL statement for dialects that use named parameters. This value may be modified when part of a compilation operation, if other `BindParameter` objects exist with the same key, or if its length is too long and truncation is required. value – Initial value for this bind param. This value may be overridden by the dictionary of parameters sent to statement compilation/execution. callable_ – A callable function that takes the place of “value”. The function will be called at statement execution time to determine the ultimate value. Used for scenarios where the actual bind value cannot be determined at the point at which the clause construct is created, but embedded bind values are still desirable. type_ – A `TypeEngine` object that will be used to pre-process the value corresponding to this `BindParameter` at execution time. unique – if True, the key name of this BindParamClause will be modified if another `BindParameter` of the same name already has been located within the containing `ClauseElement`. quote – True if this parameter name requires quoting and is not currently known as a SQLAlchemy reserved word; this currently only applies to the Oracle backend. required – a value is required at execution time. isoutparam – if True, the parameter should be treated like a stored procedure “OUT” parameter.

  `__le__`(other)
    inherited from the `__le__()` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lt__`(other)
    inherited from the `__lt__()` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__ne__`(other)
    inherited from the `__ne__()` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `anon_label`
    inherited from the `anon_label` attribute of `ColumnElement`

    provides a constant ‘anonymous label’ for this ColumnElement.

    This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.

    the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.

  `asc`()
    inherited from the `asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright)
    inherited from the `between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `collate`(collation)
    inherited from the `collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

  `compare`(other, **kw)

    Compare this `BindParameter` to the given clause.

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `concat`(other)
    inherited from the `concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)
    inherited from the `contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    In a column context, produces the clause `LIKE '%<other>%'`

  `desc`()
    inherited from the `desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  `distinct`()
    inherited from the `distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  `effective_value`

    Return the value of this bound parameter, taking into account if the `callable` parameter was set.

    The `callable` value will be evaluated and returned if present, else `value`.

  `endswith`(other, **kwargs)
    inherited from the `endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    In a column context, produces the clause `LIKE '%<other>'`

  `expression`
    inherited from the `expression` attribute of `ColumnElement`

    Return a column expression.

    Part of the inspection interface; returns self.

  `get_children`(**kwargs)
    inherited from the `get_children()` method of `ClauseElement`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `ilike`(other, escape=None)
    inherited from the `ilike()` method of `ColumnOperators`

    Implement the `ilike` operator.

    In a column context, produces the clause `a ILIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)
    inherited from the `in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

  `is_`(other)
    inherited from the `is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `isnot`(other)
    inherited from the `isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `label`(name)
    inherited from the `label()` method of `ColumnElement`

    Produce a column label, i.e. `<columnname> AS <name>`.

    This is a shortcut to the `label()` function.

    if ‘name’ is None, an anonymous label name will be generated.

  `like`(other, escape=None)
    inherited from the `like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the clause `a LIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)
    inherited from the `match()` method of `ColumnOperators`

    Implements the ‘match’ operator.

    In a column context, this produces a MATCH clause, i.e. `MATCH '<other>'`. The allowed contents of `other` are database backend specific.

  `notilike`(other, escape=None)
    inherited from the `notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)
    inherited from the `notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)
    inherited from the `notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()
    inherited from the `nullsfirst()` method of `ColumnOperators`

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()
    inherited from the `nullslast()` method of `ColumnOperators`

    Produce a `nullslast()` clause against the parent object.

  `op`(opstring, precedence=0)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument.

    See also

    Redefining and Creating New Operators

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `shares_lineage`(othercolumn)
    inherited from the `shares_lineage()` method of `ColumnElement`

    Return True if the given `ColumnElement` has a common ancestor to this `ColumnElement`.

  `startswith`(other, **kwargs)
    inherited from the `startswith()` method of `ColumnOperators`

    Implement the `startwith` operator.

    In a column context, produces the clause `LIKE '<other>%'`

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.``ClauseElement`

  Bases: `sqlalchemy.sql.visitors.Visitable`

  Base class for elements of a programmatically constructed SQL expression.

  `compare`(other, **kw)

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `get_children`(**kwargs)

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `params`(*optionaldict, **kwargs)

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `self_group`(against=None)

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `unique_params`(*optionaldict, **kwargs)

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.``ClauseList`(*clauses, **kwargs)

  Bases: `sqlalchemy.sql.expression.ClauseElement`

  Describe a list of clauses, separated by an operator.

  By default, is comma-separated, such as a column listing.

  `compare`(other, **kw)

    Compare this `ClauseList` to the given `ClauseList`, including a comparison of all the clause items.

class `sqlalchemy.sql.expression.``ColumnClause`(text, selectable=None, type_=None, is_literal=False)

  Bases: `sqlalchemy.sql.expression.Immutable`, `sqlalchemy.sql.expression.ColumnElement`

  Represents a generic column expression from any textual string.

  This includes columns associated with tables, aliases and select statements, but also any arbitrary text. May or may not be bound to an underlying `Selectable`.

  `ColumnClause` is constructed by itself typically via the `column()` function. It may be placed directly into constructs such as `select()` constructs:

      from sqlalchemy.sql import column, select

      c1, c2 = column("c1"), column("c2")
      s = select([c1, c2]).where(c1==5)

  There is also a variant on `column()` known as `literal_column()` - the difference is that in the latter case, the string value is assumed to be an exact expression, rather than a column name, so that no quoting rules or similar are applied:

      from sqlalchemy.sql import literal_column, select

      s = select([literal_column("5 + 7")])

  `ColumnClause` can also be used in a table-like fashion by combining the `column()` function with the `table()` function, to produce a “lightweight” form of table metadata:

      from sqlalchemy.sql import table, column

      user = table("user",
              column("id"),
              column("name"),
              column("description"),
      )

  The above construct can be created in an ad-hoc fashion and is not associated with any `schema.MetaData`, unlike it’s more full fledged `schema.Table` counterpart.

  Parameters: | text – the text of the element. selectable – parent selectable. type – `types.TypeEngine` object which can associate this `ColumnClause` with a type. is_literal – if True, the `ColumnClause` is assumed to be an exact expression that will be delivered to the output with no quoting rules applied regardless of case sensitive settings. the `literal_column()` function is usually used to create such a `ColumnClause`.

  `__eq__`(other)
    inherited from the `__eq__()` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__le__`(other)
    inherited from the `__le__()` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lt__`(other)
    inherited from the `__lt__()` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__ne__`(other)
    inherited from the `__ne__()` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `anon_label`
    inherited from the `anon_label` attribute of `ColumnElement`

    provides a constant ‘anonymous label’ for this ColumnElement.

    This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.

    the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.

  `asc`()
    inherited from the `asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright)
    inherited from the `between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `collate`(collation)
    inherited from the `collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

  `compare`(other, use_proxies=False, equivalents=None, **kw)
    inherited from the `compare()` method of `ColumnElement`

    Compare this ColumnElement to another.

    Special arguments understood:

    Parameters: | use_proxies – when True, consider two columns that share a common base column as equivalent (i.e. shares_lineage()) equivalents – a dictionary of columns as keys mapped to sets of columns. If the given “other” column is present in this dictionary, if any of the columns in the corresponding set() pass the comparison test, the result is True. This is used to expand the comparison to other columns that may be known to be equivalent to this one via foreign key or other criterion.

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `concat`(other)
    inherited from the `concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)
    inherited from the `contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    In a column context, produces the clause `LIKE '%<other>%'`

  `desc`()
    inherited from the `desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  `distinct`()
    inherited from the `distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  `endswith`(other, **kwargs)
    inherited from the `endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    In a column context, produces the clause `LIKE '%<other>'`

  `expression`
    inherited from the `expression` attribute of `ColumnElement`

    Return a column expression.

    Part of the inspection interface; returns self.

  `get_children`(**kwargs)
    inherited from the `get_children()` method of `ClauseElement`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `ilike`(other, escape=None)
    inherited from the `ilike()` method of `ColumnOperators`

    Implement the `ilike` operator.

    In a column context, produces the clause `a ILIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)
    inherited from the `in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

  `is_`(other)
    inherited from the `is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `isnot`(other)
    inherited from the `isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `label`(name)
    inherited from the `label()` method of `ColumnElement`

    Produce a column label, i.e. `<columnname> AS <name>`.

    This is a shortcut to the `label()` function.

    if ‘name’ is None, an anonymous label name will be generated.

  `like`(other, escape=None)
    inherited from the `like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the clause `a LIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)
    inherited from the `match()` method of `ColumnOperators`

    Implements the ‘match’ operator.

    In a column context, this produces a MATCH clause, i.e. `MATCH '<other>'`. The allowed contents of `other` are database backend specific.

  `notilike`(other, escape=None)
    inherited from the `notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)
    inherited from the `notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)
    inherited from the `notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()
    inherited from the `nullsfirst()` method of `ColumnOperators`

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()
    inherited from the `nullslast()` method of `ColumnOperators`

    Produce a `nullslast()` clause against the parent object.

  `op`(opstring, precedence=0)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument.

    See also

    Redefining and Creating New Operators

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `shares_lineage`(othercolumn)
    inherited from the `shares_lineage()` method of `ColumnElement`

    Return True if the given `ColumnElement` has a common ancestor to this `ColumnElement`.

  `startswith`(other, **kwargs)
    inherited from the `startswith()` method of `ColumnOperators`

    Implement the `startwith` operator.

    In a column context, produces the clause `LIKE '<other>%'`

class `sqlalchemy.sql.expression.``ColumnCollection`(*cols)

  Bases: `sqlalchemy.util._collections.OrderedProperties`

  An ordered dictionary that stores a list of ColumnElement instances.

  Overrides the `__eq__()` method to produce SQL clauses between sets of correlated columns.

  `add`(column)

    Add a column to this collection.

    The key attribute of the column will be used as the hash key for this dictionary.

  `replace`(column)

    add the given column to this collection, removing unaliased versions of this column as well as existing columns with the same key.

    > e.g.:

    >     t = Table('sometable', metadata, Column('col1', Integer))
    >     t.columns.replace(Column('col1', Integer, key='columnone'))

    > will remove the original ‘col1’ from the collection, and add the new column under the name ‘columnname’.

    Used by schema.Column to override columns during table reflection.

class `sqlalchemy.sql.expression.``ColumnElement`

  Bases: `sqlalchemy.sql.expression.ClauseElement`, `sqlalchemy.sql.operators.ColumnOperators`

  Represent a column-oriented SQL expression suitable for usage in the “columns” clause, WHERE clause etc. of a statement.

  While the most familiar kind of `ColumnElement` is the `Column` object, `ColumnElement` serves as the basis for any unit that may be present in a SQL expression, including the expressions themselves, SQL functions, bound parameters, literal expressions, keywords such as `NULL`, etc. `ColumnElement` is the ultimate base class for all such elements.

  A `ColumnElement` provides the ability to generate new `ColumnElement` objects using Python expressions. This means that Python operators such as `==`, `!=` and `<` are overloaded to mimic SQL operations, and allow the instantiation of further `ColumnElement` instances which are composed from other, more fundamental `ColumnElement` objects. For example, two `ColumnClause` objects can be added together with the addition operator `+` to produce a `BinaryExpression`. Both `ColumnClause` and `BinaryExpression` are subclasses of `ColumnElement`:

      >>> from sqlalchemy.sql import column
      >>> column('a') + column('b')
      <sqlalchemy.sql.expression.BinaryExpression object at 0x101029dd0>
      >>> print column('a') + column('b')
      a + b

  `ColumnElement` supports the ability to be a proxy element, which indicates that the `ColumnElement` may be associated with a `Selectable` which was derived from another `Selectable`. An example of a “derived” `Selectable` is an `Alias` of a `Table`. For the ambitious, an in-depth discussion of this concept can be found at Expression Transformations.

  `__eq__`(other)
    inherited from the `__eq__()` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__init__`
    inherited from the `__init__` attribute of `object`

    x.__init__(...) initializes x; see help(type(x)) for signature

  `__le__`(other)
    inherited from the `__le__()` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lt__`(other)
    inherited from the `__lt__()` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__ne__`(other)
    inherited from the `__ne__()` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `anon_label`

    provides a constant ‘anonymous label’ for this ColumnElement.

    This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.

    the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.

  `asc`()
    inherited from the `asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright)
    inherited from the `between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `collate`(collation)
    inherited from the `collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

  `compare`(other, use_proxies=False, equivalents=None, **kw)

    Compare this ColumnElement to another.

    Special arguments understood:

    Parameters: | use_proxies – when True, consider two columns that share a common base column as equivalent (i.e. shares_lineage()) equivalents – a dictionary of columns as keys mapped to sets of columns. If the given “other” column is present in this dictionary, if any of the columns in the corresponding set() pass the comparison test, the result is True. This is used to expand the comparison to other columns that may be known to be equivalent to this one via foreign key or other criterion.

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `concat`(other)
    inherited from the `concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)
    inherited from the `contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    In a column context, produces the clause `LIKE '%<other>%'`

  `desc`()
    inherited from the `desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  `distinct`()
    inherited from the `distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  `endswith`(other, **kwargs)
    inherited from the `endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    In a column context, produces the clause `LIKE '%<other>'`

  `expression`

    Return a column expression.

    Part of the inspection interface; returns self.

  `get_children`(**kwargs)
    inherited from the `get_children()` method of `ClauseElement`

    Return immediate child elements of this `ClauseElement`.

    This is used for visit traversal.

    **kwargs may contain flags that change the collection that is returned, for example to return a subset of items in order to cut down on larger traversals, or to return child items from a different context (such as schema-level collections instead of clause-level).

  `ilike`(other, escape=None)
    inherited from the `ilike()` method of `ColumnOperators`

    Implement the `ilike` operator.

    In a column context, produces the clause `a ILIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)
    inherited from the `in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

  `is_`(other)
    inherited from the `is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `isnot`(other)
    inherited from the `isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `label`(name)

    Produce a column label, i.e. `<columnname> AS <name>`.

    This is a shortcut to the `label()` function.

    if ‘name’ is None, an anonymous label name will be generated.

  `like`(other, escape=None)
    inherited from the `like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the clause `a LIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)
    inherited from the `match()` method of `ColumnOperators`

    Implements the ‘match’ operator.

    In a column context, this produces a MATCH clause, i.e. `MATCH '<other>'`. The allowed contents of `other` are database backend specific.

  `notilike`(other, escape=None)
    inherited from the `notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)
    inherited from the `notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)
    inherited from the `notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()
    inherited from the `nullsfirst()` method of `ColumnOperators`

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()
    inherited from the `nullslast()` method of `ColumnOperators`

    Produce a `nullslast()` clause against the parent object.

  `op`(opstring, precedence=0)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument.

    See also

    Redefining and Creating New Operators

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `shares_lineage`(othercolumn)

    Return True if the given `ColumnElement` has a common ancestor to this `ColumnElement`.

  `startswith`(other, **kwargs)
    inherited from the `startswith()` method of `ColumnOperators`

    Implement the `startwith` operator.

    In a column context, produces the clause `LIKE '<other>%'`

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.operators.``ColumnOperators`

  Bases: `sqlalchemy.sql.operators.Operators`

  Defines boolean, comparison, and other operators for `ColumnElement` expressions.

  By default, all methods call down to `operate()` or `reverse_operate()`, passing in the appropriate operator function from the Python builtin `operator` module or a SQLAlchemy-specific operator function from `sqlalchemy.expression.operators`. For example the `__eq__` function:

      def __eq__(self, other):
          return self.operate(operators.eq, other)

  Where `operators.eq` is essentially:

      def eq(a, b):
          return a == b

  The core column expression unit `ColumnElement` overrides `Operators.operate()` and others to return further `ColumnElement` constructs, so that the `==` operation above is replaced by a clause construct.

  See also:

  Redefining and Creating New Operators

  `TypeEngine.comparator_factory`

  `ColumnOperators`

  `PropComparator`

  `__add__`(other)

    Implement the `+` operator.

    In a column context, produces the clause `a + b` if the parent object has non-string affinity. If the parent object has a string affinity, produces the concatenation operator, `a || b` - see `ColumnOperators.concat()`.

  `__and__`(other)
    inherited from the `__and__()` method of `Operators`

    Implement the `&` operator.

    When used with SQL expressions, results in an AND operation, equivalent to `and_()`, that is:

        a & b

    is equivalent to:

        from sqlalchemy import and_
        and_(a, b)

    Care should be taken when using `&` regarding operator precedence; the `&` operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:

        (a == 2) & (b == 4)

  `__delattr__`
    inherited from the `__delattr__` attribute of `object`

    x.__delattr__(‘name’) <==> del x.name

  `__div__`(other)

    Implement the `/` operator.

    In a column context, produces the clause `a / b`.

  `__eq__`(other)

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__format__`()
    inherited from the `__format__()` method of `object`

    default object formatter

  `__ge__`(other)

    Implement the `>=` operator.

    In a column context, produces the clause `a >= b`.

  `__getattribute__`
    inherited from the `__getattribute__` attribute of `object`

    x.__getattribute__(‘name’) <==> x.name

  `__getitem__`(index)

    Implement the [] operator.

    This can be used by some database-specific types such as Postgresql ARRAY and HSTORE.

  `__gt__`(other)

    Implement the `>` operator.

    In a column context, produces the clause `a > b`.

  `__hash__`

    x.__hash__() <==> hash(x)

  `__init__`
    inherited from the `__init__` attribute of `object`

    x.__init__(...) initializes x; see help(type(x)) for signature

  `__invert__`()
    inherited from the `__invert__()` method of `Operators`

    Implement the `~` operator.

    When used with SQL expressions, results in a NOT operation, equivalent to `not_()`, that is:

        ~a

    is equivalent to:

        from sqlalchemy import not_
        not_(a)

  `__le__`(other)

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lshift__`(other)

    implement the << operator.

    Not used by SQLAlchemy core, this is provided for custom operator systems which want to use << as an extension point.

  `__lt__`(other)

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__mod__`(other)

    Implement the `%` operator.

    In a column context, produces the clause `a % b`.

  `__mul__`(other)

    Implement the `*` operator.

    In a column context, produces the clause `a * b`.

  `__ne__`(other)

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `__neg__`()

    Implement the `-` operator.

    In a column context, produces the clause `-a`.

  static `__new__`(S, ...) → a new object with type S, a subtype of T
    inherited from the `__new__()` method of `object`
  `__or__`(other)
    inherited from the `__or__()` method of `Operators`

    Implement the `|` operator.

    When used with SQL expressions, results in an OR operation, equivalent to `or_()`, that is:

        a | b

    is equivalent to:

        from sqlalchemy import or_
        or_(a, b)

    Care should be taken when using `|` regarding operator precedence; the `|` operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:

        (a == 2) | (b == 4)

  `__radd__`(other)

    Implement the `+` operator in reverse.

    See `ColumnOperators.__add__()`.

  `__rdiv__`(other)

    Implement the `/` operator in reverse.

    See `ColumnOperators.__div__()`.

  `__reduce__`()
    inherited from the `__reduce__()` method of `object`

    helper for pickle

  `__reduce_ex__`()
    inherited from the `__reduce_ex__()` method of `object`

    helper for pickle

  `__repr__`
    inherited from the `__repr__` attribute of `object`

    x.__repr__() <==> repr(x)

  `__rmul__`(other)

    Implement the `*` operator in reverse.

    See `ColumnOperators.__mul__()`.

  `__rshift__`(other)

    implement the >> operator.

    Not used by SQLAlchemy core, this is provided for custom operator systems which want to use >> as an extension point.

  `__rsub__`(other)

    Implement the `-` operator in reverse.

    See `ColumnOperators.__sub__()`.

  `__rtruediv__`(other)

    Implement the `//` operator in reverse.

    See `ColumnOperators.__truediv__()`.

  `__setattr__`
    inherited from the `__setattr__` attribute of `object`

    x.__setattr__(‘name’, value) <==> x.name = value

  `__sizeof__`() → int
    inherited from the `__sizeof__()` method of `object`

    size of object in memory, in bytes

  `__str__`
    inherited from the `__str__` attribute of `object`

    x.__str__() <==> str(x)

  `__sub__`(other)

    Implement the `-` operator.

    In a column context, produces the clause `a - b`.

  static `__subclasshook__`()
    inherited from the `__subclasshook__()` method of `object`

    Abstract classes can override this to customize issubclass().

    This is invoked early on by abc.ABCMeta.__subclasscheck__(). It should return True, False or NotImplemented. If it returns NotImplemented, the normal algorithm is used. Otherwise, it overrides the normal algorithm (and the outcome is cached).

  `__truediv__`(other)

    Implement the `//` operator.

    In a column context, produces the clause `a / b`.

  `__weakref__`
    inherited from the `__weakref__` attribute of `Operators`

    list of weak references to the object (if defined)

  `asc`()

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright)

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `collate`(collation)

    Produce a `collate()` clause against the parent object, given the collation string.

  `concat`(other)

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)

    Implement the ‘contains’ operator.

    In a column context, produces the clause `LIKE '%<other>%'`

  `desc`()

    Produce a `desc()` clause against the parent object.

  `distinct`()

    Produce a `distinct()` clause against the parent object.

  `endswith`(other, **kwargs)

    Implement the ‘endswith’ operator.

    In a column context, produces the clause `LIKE '%<other>'`

  `ilike`(other, escape=None)

    Implement the `ilike` operator.

    In a column context, produces the clause `a ILIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

  `is_`(other)

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `isnot`(other)

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `like`(other, escape=None)

    Implement the `like` operator.

    In a column context, produces the clause `a LIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)

    Implements the ‘match’ operator.

    In a column context, this produces a MATCH clause, i.e. `MATCH '<other>'`. The allowed contents of `other` are database backend specific.

  `notilike`(other, escape=None)

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()

    Produce a `nullslast()` clause against the parent object.

  `op`(opstring, precedence=0)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument.

    See also

    Redefining and Creating New Operators

  `operate`(op, *other, **kwargs)
    inherited from the `operate()` method of `Operators`

    Operate on an argument.

    This is the lowest level of operation, raises `NotImplementedError` by default.

    Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

        class MyComparator(ColumnOperators):
            def operate(self, op, other):
                return op(func.lower(self), func.lower(other))

    Parameters: | op – Operator callable. *other – the ‘other’ side of the operation. Will be a single scalar for most operations. **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

  `reverse_operate`(op, other, **kwargs)
    inherited from the `reverse_operate()` method of `Operators`

    Reverse operate on an argument.

    Usage is the same as `operate()`.

  `startswith`(other, **kwargs)

    Implement the `startwith` operator.

    In a column context, produces the clause `LIKE '<other>%'`

  `timetuple` = None

    Hack, allows datetime objects to be compared on the LHS.

class `sqlalchemy.sql.expression.``CompoundSelect`(keyword, *selects, **kwargs)

  Bases: `sqlalchemy.sql.expression.SelectBase`

  Forms the basis of `UNION`, `UNION ALL`, and other SELECT-based set operations.

  `alias`(name=None)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `append_group_by`(*clauses)
    inherited from the `append_group_by()` method of `SelectBase`

    Append the given GROUP BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing GROUP BY criterion.

    This is an in-place mutation method; the `group_by()` method is preferred, as it provides standard method chaining.

  `append_order_by`(*clauses)
    inherited from the `append_order_by()` method of `SelectBase`

    Append the given ORDER BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing ORDER BY criterion.

    This is an in-place mutation method; the `order_by()` method is preferred, as it provides standard method chaining.

  `apply_labels`()
    inherited from the `apply_labels()` method of `SelectBase`

    return a new selectable with the ‘use_labels’ flag set to True.

    This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.

  `as_scalar`()
    inherited from the `as_scalar()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, which can be used as a column expression.

    Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.

    The returned object is an instance of `ScalarSelect`.

  `autocommit`()
    inherited from the `autocommit()` method of `SelectBase`

    return a new selectable with the ‘autocommit’ flag set to

    Deprecated since version 0.6: `autocommit()` is deprecated. Use `Executable.execution_options()` with the ‘autocommit’ flag.

    True.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

  `cte`(name=None, recursive=False)
    inherited from the `cte()` method of `SelectBase`

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    New in version 0.7.6.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples illustrate two examples from Postgresql’s documentation at http://www.postgresql.org/docs/8.4/static/queries-with.html.

    Example 1, non recursive:

        from sqlalchemy import Table, Column, String, Integer, MetaData, \
            select, func

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import Table, Column, String, Integer, MetaData, \
            select, func

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.part,
                parts_alias.c.sub_part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).                    select_from(included_parts.join(parts,
                            included_parts.c.part==parts.c.part)).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    See also

    `orm.query.Query.cte()` - ORM version of `SelectBase.cte()`.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `group_by`(*clauses)
    inherited from the `group_by()` method of `SelectBase`

    return a new selectable with the given list of GROUP BY criterion applied.

    The criterion will be appended to any pre-existing GROUP BY criterion.

  `join`(right, onclause=None, isouter=False)
    inherited from the `join()` method of `FromClause`

    return a join of this `FromClause` against another `FromClause`.

  `label`(name)
    inherited from the `label()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.

    See also

    `as_scalar()`.

  `limit`(limit)
    inherited from the `limit()` method of `SelectBase`

    return a new selectable with the given LIMIT criterion applied.

  `offset`(offset)
    inherited from the `offset()` method of `SelectBase`

    return a new selectable with the given OFFSET criterion applied.

  `order_by`(*clauses)
    inherited from the `order_by()` method of `SelectBase`

    return a new selectable with the given list of ORDER BY criterion applied.

    The criterion will be appended to any pre-existing ORDER BY criterion.

  `outerjoin`(right, onclause=None)
    inherited from the `outerjoin()` method of `FromClause`

    return an outer join of this `FromClause` against another `FromClause`.

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.operators.``custom_op`(opstring, precedence=0)

  Represent a ‘custom’ operator.

  `custom_op` is normally instantitated when the `ColumnOperators.op()` method is used to create a custom operator callable. The class can also be used directly when programmatically constructing expressions. E.g. to represent the “factorial” operation:

      from sqlalchemy.sql import UnaryExpression
      from sqlalchemy.sql import operators
      from sqlalchemy import Numeric

      unary = UnaryExpression(table.c.somecolumn,
              modifier=operators.custom_op("!"),
              type_=Numeric)

class `sqlalchemy.sql.expression.``CTE`(selectable, name=None, recursive=False, cte_alias=False, _restates=frozenset([]))

  Bases: `sqlalchemy.sql.expression.Alias`

  Represent a Common Table Expression.

  The `CTE` object is obtained using the `SelectBase.cte()` method from any selectable. See that method for complete examples.

  New in version 0.7.6.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `join`(right, onclause=None, isouter=False)
    inherited from the `join()` method of `FromClause`

    return a join of this `FromClause` against another `FromClause`.

  `outerjoin`(right, onclause=None)
    inherited from the `outerjoin()` method of `FromClause`

    return an outer join of this `FromClause` against another `FromClause`.

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.``Delete`(table, whereclause, bind=None, returning=None, prefixes=None, **kwargs)

  Bases: `sqlalchemy.sql.expression.UpdateBase`

  Represent a DELETE construct.

  The `Delete` object is created using the `delete()` function.

  `bind`
    inherited from the `bind` attribute of `UpdateBase`

    Return a ‘bind’ linked to this `UpdateBase` or a `Table` associated with it.

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `params`(*arg, **kw)
    inherited from the `params()` method of `UpdateBase`

    Set the parameters for the statement.

    This method raises `NotImplementedError` on the base class, and is overridden by `ValuesBase` to provide the SET/VALUES clause of UPDATE and INSERT.

  `prefix_with`(*expr, **kw)
    inherited from the `prefix_with()` method of `HasPrefixes`

    Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.

    This is used to support backend-specific prefix keywords such as those provided by MySQL.

    E.g.:

        stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")

    Multiple prefixes can be specified by multiple calls to `prefix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the INSERT, UPDATE, or DELETE keyword. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this prefix to only that dialect.

  `returning`(*cols)
    inherited from the `returning()` method of `UpdateBase`

    Add a RETURNING or equivalent clause to this statement.

    The given list of columns represent columns within the table that is the target of the INSERT, UPDATE, or DELETE. Each element can be any column expression. `Table` objects will be expanded into their individual columns.

    Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.

    Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using `fetchone()` and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.

    Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

  `where`(whereclause)

    Add the given WHERE clause to a newly returned delete construct.

  `with_hint`(text, selectable=None, dialect_name='*')
    inherited from the `with_hint()` method of `UpdateBase`

    Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.

    Note

    `UpdateBase.with_hint()` currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use `UpdateBase.prefix_with()`.

    The text of the hint is rendered in the appropriate location for the database backend in use, relative to the `Table` that is the subject of this statement, or optionally to that of the given `Table` passed as the `selectable` argument.

    The `dialect_name` option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:

        mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")

    New in version 0.7.6.

    Parameters: | text – Text of the hint. selectable – optional `Table` that specifies an element of the FROM clause within an UPDATE or DELETE to be the subject of the hint - applies only to certain backends. dialect_name – defaults to `*`, if specified as the name of a particular dialect, will apply these hints only when that dialect is in use.

class `sqlalchemy.sql.expression.``Executable`

  Bases: `sqlalchemy.sql.expression.Generative`

  Mark a ClauseElement as supporting execution.

  `Executable` is a superclass for all “statement” types of objects, including `select()`, `delete()`, `update()`, `insert()`, `text()`.

  `bind`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `execute`(*multiparams, **params)

    Compile and execute this `Executable`.

  `execution_options`(**kw)

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `scalar`(*multiparams, **params)

    Compile and execute this `Executable`, returning the result’s scalar representation.

class `sqlalchemy.sql.expression.``FunctionElement`(*clauses, **kwargs)

  Bases: `sqlalchemy.sql.expression.Executable`, `sqlalchemy.sql.expression.ColumnElement`, `sqlalchemy.sql.expression.FromClause`

  Base for SQL function-oriented constructs.

  See also

  `Function` - named SQL function.

  `func` - namespace which produces registered or ad-hoc `Function` instances.

  `GenericFunction` - allows creation of registered function types.

  `__eq__`(other)
    inherited from the `__eq__()` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__init__`(*clauses, **kwargs)

    Construct a `FunctionElement`.

  `__le__`(other)
    inherited from the `__le__()` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lt__`(other)
    inherited from the `__lt__()` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__ne__`(other)
    inherited from the `__ne__()` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `alias`(name=None)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `anon_label`
    inherited from the `anon_label` attribute of `ColumnElement`

    provides a constant ‘anonymous label’ for this ColumnElement.

    This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.

    the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.

  `asc`()
    inherited from the `asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright)
    inherited from the `between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `bind`
    inherited from the `bind` attribute of `Executable`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `clauses`

    Return the underlying `ClauseList` which contains the arguments for this `FunctionElement`.

  `collate`(collation)
    inherited from the `collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

  `columns`

    Fulfill the ‘columns’ contract of `ColumnElement`.

    Returns a single-element list consisting of this object.

  `compare`(other, use_proxies=False, equivalents=None, **kw)
    inherited from the `compare()` method of `ColumnElement`

    Compare this ColumnElement to another.

    Special arguments understood:

    Parameters: | use_proxies – when True, consider two columns that share a common base column as equivalent (i.e. shares_lineage()) equivalents – a dictionary of columns as keys mapped to sets of columns. If the given “other” column is present in this dictionary, if any of the columns in the corresponding set() pass the comparison test, the result is True. This is used to expand the comparison to other columns that may be known to be equivalent to this one via foreign key or other criterion.

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `concat`(other)
    inherited from the `concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)
    inherited from the `contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    In a column context, produces the clause `LIKE '%<other>%'`

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

  `desc`()
    inherited from the `desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `distinct`()
    inherited from the `distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  `endswith`(other, **kwargs)
    inherited from the `endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    In a column context, produces the clause `LIKE '%<other>'`

  `execute`()

    Execute this `FunctionElement` against an embedded ‘bind’.

    This first calls `select()` to produce a SELECT construct.

    Note that `FunctionElement` can be passed to the `Connectable.execute()` method of `Connection` or `Engine`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `expression`
    inherited from the `expression` attribute of `ColumnElement`

    Return a column expression.

    Part of the inspection interface; returns self.

  `ilike`(other, escape=None)
    inherited from the `ilike()` method of `ColumnOperators`

    Implement the `ilike` operator.

    In a column context, produces the clause `a ILIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)
    inherited from the `in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

  `is_`(other)
    inherited from the `is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `FromClause`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `isnot`(other)
    inherited from the `isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `join`(right, onclause=None, isouter=False)
    inherited from the `join()` method of `FromClause`

    return a join of this `FromClause` against another `FromClause`.

  `label`(name)
    inherited from the `label()` method of `ColumnElement`

    Produce a column label, i.e. `<columnname> AS <name>`.

    This is a shortcut to the `label()` function.

    if ‘name’ is None, an anonymous label name will be generated.

  `like`(other, escape=None)
    inherited from the `like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the clause `a LIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)
    inherited from the `match()` method of `ColumnOperators`

    Implements the ‘match’ operator.

    In a column context, this produces a MATCH clause, i.e. `MATCH '<other>'`. The allowed contents of `other` are database backend specific.

  `notilike`(other, escape=None)
    inherited from the `notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)
    inherited from the `notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)
    inherited from the `notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()
    inherited from the `nullsfirst()` method of `ColumnOperators`

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()
    inherited from the `nullslast()` method of `ColumnOperators`

    Produce a `nullslast()` clause against the parent object.

  `op`(opstring, precedence=0)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument.

    See also

    Redefining and Creating New Operators

  `outerjoin`(right, onclause=None)
    inherited from the `outerjoin()` method of `FromClause`

    return an outer join of this `FromClause` against another `FromClause`.

  `over`(partition_by=None, order_by=None)

    Produce an OVER clause against this function.

    Used against aggregate or so-called “window” functions, for database backends that support window functions.

    The expression:

        func.row_number().over(order_by='x')

    is shorthand for:

        from sqlalchemy import over
        over(func.row_number(), order_by='x')

    See `over()` for a full description.

    New in version 0.7.

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `replace_selectable`(old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`()

    Execute this `FunctionElement` against an embedded ‘bind’ and return a scalar value.

    This first calls `select()` to produce a SELECT construct.

    Note that `FunctionElement` can be passed to the `Connectable.scalar()` method of `Connection` or `Engine`.

  `select`()

    Produce a `select()` construct against this `FunctionElement`.

    This is shorthand for:

        s = select([function_element])

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `shares_lineage`(othercolumn)
    inherited from the `shares_lineage()` method of `ColumnElement`

    Return True if the given `ColumnElement` has a common ancestor to this `ColumnElement`.

  `startswith`(other, **kwargs)
    inherited from the `startswith()` method of `ColumnOperators`

    Implement the `startwith` operator.

    In a column context, produces the clause `LIKE '<other>%'`

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.``Function`(name, *clauses, **kw)

  Bases: `sqlalchemy.sql.expression.FunctionElement`

  Describe a named SQL function.

  See the superclass `FunctionElement` for a description of public methods.

  See also

  `func` - namespace which produces registered or ad-hoc `Function` instances.

  `GenericFunction` - allows creation of registered function types.

  `__eq__`(other)
    inherited from the `__eq__()` method of `ColumnOperators`

    Implement the `==` operator.

    In a column context, produces the clause `a = b`. If the target is `None`, produces `a IS NULL`.

  `__init__`(name, *clauses, **kw)

    Construct a `Function`.

    The `func` construct is normally used to construct new `Function` instances.

  `__le__`(other)
    inherited from the `__le__()` method of `ColumnOperators`

    Implement the `<=` operator.

    In a column context, produces the clause `a <= b`.

  `__lt__`(other)
    inherited from the `__lt__()` method of `ColumnOperators`

    Implement the `<` operator.

    In a column context, produces the clause `a < b`.

  `__ne__`(other)
    inherited from the `__ne__()` method of `ColumnOperators`

    Implement the `!=` operator.

    In a column context, produces the clause `a != b`. If the target is `None`, produces `a IS NOT NULL`.

  `alias`(name=None)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `anon_label`
    inherited from the `anon_label` attribute of `ColumnElement`

    provides a constant ‘anonymous label’ for this ColumnElement.

    This is a label() expression which will be named at compile time. The same label() is returned each time anon_label is called so that expressions can reference anon_label multiple times, producing the same label name at compile time.

    the compiler uses this function automatically at compile time for expressions that are known to be ‘unnamed’ like binary expressions and function calls.

  `asc`()
    inherited from the `asc()` method of `ColumnOperators`

    Produce a `asc()` clause against the parent object.

  `between`(cleft, cright)
    inherited from the `between()` method of `ColumnOperators`

    Produce a `between()` clause against the parent object, given the lower and upper range.

  `bind`
    inherited from the `bind` attribute of `Executable`

    Returns the `Engine` or `Connection` to which this `Executable` is bound, or None if none found.

    This is a traversal which checks locally, then checks among the “from” clauses of associated objects until a bound engine or connection is found.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `clauses`
    inherited from the `clauses` attribute of `FunctionElement`

    Return the underlying `ClauseList` which contains the arguments for this `FunctionElement`.

  `collate`(collation)
    inherited from the `collate()` method of `ColumnOperators`

    Produce a `collate()` clause against the parent object, given the collation string.

  `columns`
    inherited from the `columns` attribute of `FunctionElement`

    Fulfill the ‘columns’ contract of `ColumnElement`.

    Returns a single-element list consisting of this object.

  `compare`(other, use_proxies=False, equivalents=None, **kw)
    inherited from the `compare()` method of `ColumnElement`

    Compare this ColumnElement to another.

    Special arguments understood:

    Parameters: | use_proxies – when True, consider two columns that share a common base column as equivalent (i.e. shares_lineage()) equivalents – a dictionary of columns as keys mapped to sets of columns. If the given “other” column is present in this dictionary, if any of the columns in the corresponding set() pass the comparison test, the result is True. This is used to expand the comparison to other columns that may be known to be equivalent to this one via foreign key or other criterion.

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `concat`(other)
    inherited from the `concat()` method of `ColumnOperators`

    Implement the ‘concat’ operator.

    In a column context, produces the clause `a || b`, or uses the `concat()` operator on MySQL.

  `contains`(other, **kwargs)
    inherited from the `contains()` method of `ColumnOperators`

    Implement the ‘contains’ operator.

    In a column context, produces the clause `LIKE '%<other>%'`

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

  `desc`()
    inherited from the `desc()` method of `ColumnOperators`

    Produce a `desc()` clause against the parent object.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `distinct`()
    inherited from the `distinct()` method of `ColumnOperators`

    Produce a `distinct()` clause against the parent object.

  `endswith`(other, **kwargs)
    inherited from the `endswith()` method of `ColumnOperators`

    Implement the ‘endswith’ operator.

    In a column context, produces the clause `LIKE '%<other>'`

  `execute`()
    inherited from the `execute()` method of `FunctionElement`

    Execute this `FunctionElement` against an embedded ‘bind’.

    This first calls `select()` to produce a SELECT construct.

    Note that `FunctionElement` can be passed to the `Connectable.execute()` method of `Connection` or `Engine`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `expression`
    inherited from the `expression` attribute of `ColumnElement`

    Return a column expression.

    Part of the inspection interface; returns self.

  `ilike`(other, escape=None)
    inherited from the `ilike()` method of `ColumnOperators`

    Implement the `ilike` operator.

    In a column context, produces the clause `a ILIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.ilike("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.ilike("foo/%bar", escape="/")

    See also

    `ColumnOperators.like()`

  `in_`(other)
    inherited from the `in_()` method of `ColumnOperators`

    Implement the `in` operator.

    In a column context, produces the clause `a IN other`. “other” may be a tuple/list of column expressions, or a `select()` construct.

  `is_`(other)
    inherited from the `is_()` method of `ColumnOperators`

    Implement the `IS` operator.

    Normally, `IS` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.isnot()`

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `FromClause`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `isnot`(other)
    inherited from the `isnot()` method of `ColumnOperators`

    Implement the `IS NOT` operator.

    Normally, `IS NOT` is generated automatically when comparing to a value of `None`, which resolves to `NULL`. However, explicit usage of `IS NOT` may be desirable if comparing to boolean values on certain platforms.

    New in version 0.7.9.

    See also

    `ColumnOperators.is_()`

  `join`(right, onclause=None, isouter=False)
    inherited from the `join()` method of `FromClause`

    return a join of this `FromClause` against another `FromClause`.

  `label`(name)
    inherited from the `label()` method of `ColumnElement`

    Produce a column label, i.e. `<columnname> AS <name>`.

    This is a shortcut to the `label()` function.

    if ‘name’ is None, an anonymous label name will be generated.

  `like`(other, escape=None)
    inherited from the `like()` method of `ColumnOperators`

    Implement the `like` operator.

    In a column context, produces the clause `a LIKE other`.

    E.g.:

        select([sometable]).where(sometable.c.column.like("%foobar%"))

    - Parameters: | other – expression to be compared escape – optional escape character, renders the `ESCAPE` keyword, e.g.:
          somecolumn.like("foo/%bar", escape="/")

    See also

    `ColumnOperators.ilike()`

  `match`(other, **kwargs)
    inherited from the `match()` method of `ColumnOperators`

    Implements the ‘match’ operator.

    In a column context, this produces a MATCH clause, i.e. `MATCH '<other>'`. The allowed contents of `other` are database backend specific.

  `notilike`(other, escape=None)
    inherited from the `notilike()` method of `ColumnOperators`

    implement the `NOT ILIKE` operator.

    This is equivalent to using negation with `ColumnOperators.ilike()`, i.e. `~x.ilike(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.ilike()`

  `notin_`(other)
    inherited from the `notin_()` method of `ColumnOperators`

    implement the `NOT IN` operator.

    This is equivalent to using negation with `ColumnOperators.in_()`, i.e. `~x.in_(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.in_()`

  `notlike`(other, escape=None)
    inherited from the `notlike()` method of `ColumnOperators`

    implement the `NOT LIKE` operator.

    This is equivalent to using negation with `ColumnOperators.like()`, i.e. `~x.like(y)`.

    New in version 0.8.

    See also

    `ColumnOperators.like()`

  `nullsfirst`()
    inherited from the `nullsfirst()` method of `ColumnOperators`

    Produce a `nullsfirst()` clause against the parent object.

  `nullslast`()
    inherited from the `nullslast()` method of `ColumnOperators`

    Produce a `nullslast()` clause against the parent object.

  `op`(opstring, precedence=0)
    inherited from the `op()` method of `Operators`

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument.

    See also

    Redefining and Creating New Operators

  `outerjoin`(right, onclause=None)
    inherited from the `outerjoin()` method of `FromClause`

    return an outer join of this `FromClause` against another `FromClause`.

  `over`(partition_by=None, order_by=None)
    inherited from the `over()` method of `FunctionElement`

    Produce an OVER clause against this function.

    Used against aggregate or so-called “window” functions, for database backends that support window functions.

    The expression:

        func.row_number().over(order_by='x')

    is shorthand for:

        from sqlalchemy import over
        over(func.row_number(), order_by='x')

    See `over()` for a full description.

    New in version 0.7.

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `replace_selectable`(old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`()
    inherited from the `scalar()` method of `FunctionElement`

    Execute this `FunctionElement` against an embedded ‘bind’ and return a scalar value.

    This first calls `select()` to produce a SELECT construct.

    Note that `FunctionElement` can be passed to the `Connectable.scalar()` method of `Connection` or `Engine`.

  `select`()
    inherited from the `select()` method of `FunctionElement`

    Produce a `select()` construct against this `FunctionElement`.

    This is shorthand for:

        s = select([function_element])

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `shares_lineage`(othercolumn)
    inherited from the `shares_lineage()` method of `ColumnElement`

    Return True if the given `ColumnElement` has a common ancestor to this `ColumnElement`.

  `startswith`(other, **kwargs)
    inherited from the `startswith()` method of `ColumnOperators`

    Implement the `startwith` operator.

    In a column context, produces the clause `LIKE '<other>%'`

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.expression.``FromClause`

  Bases: `sqlalchemy.sql.expression.Selectable`

  Represent an element that can be used within the `FROM` clause of a `SELECT` statement.

  The most common forms of `FromClause` are the `Table` and the `select()` constructs. Key features common to all `FromClause` objects include:

  - a `c` collection, which provides per-name access to a collection of `ColumnElement` objects.
  - a `primary_key` attribute, which is a collection of all those `ColumnElement` objects that indicate the `primary_key` flag.
  - Methods to generate various derivations of a “from” clause, including `FromClause.alias()`, `FromClause.join()`, `FromClause.select()`.
  `alias`(name=None)

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`

    An alias for the `columns` attribute.

  `columns`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `correspond_on_equivalents`(column, equivalents)

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)

    return a SELECT COUNT generated against this `FromClause`.

  `description`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `foreign_keys`

    Return the collection of ForeignKey objects which this FromClause references.

  `is_derived_from`(fromclause)

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False)

    return a join of this `FromClause` against another `FromClause`.

  `outerjoin`(right, onclause=None)

    return an outer join of this `FromClause` against another `FromClause`.

  `primary_key`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(old, alias)

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

class `sqlalchemy.sql.expression.``Insert`(table, values=None, inline=False, bind=None, prefixes=None, returning=None, **kwargs)

  Bases: `sqlalchemy.sql.expression.ValuesBase`

  Represent an INSERT construct.

  The `Insert` object is created using the `insert()` function.

  See also

  Insert Expressions

  `bind`
    inherited from the `bind` attribute of `UpdateBase`

    Return a ‘bind’ linked to this `UpdateBase` or a `Table` associated with it.

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `params`(*arg, **kw)
    inherited from the `params()` method of `UpdateBase`

    Set the parameters for the statement.

    This method raises `NotImplementedError` on the base class, and is overridden by `ValuesBase` to provide the SET/VALUES clause of UPDATE and INSERT.

  `prefix_with`(*expr, **kw)
    inherited from the `prefix_with()` method of `HasPrefixes`

    Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.

    This is used to support backend-specific prefix keywords such as those provided by MySQL.

    E.g.:

        stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")

    Multiple prefixes can be specified by multiple calls to `prefix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the INSERT, UPDATE, or DELETE keyword. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this prefix to only that dialect.

  `returning`(*cols)
    inherited from the `returning()` method of `UpdateBase`

    Add a RETURNING or equivalent clause to this statement.

    The given list of columns represent columns within the table that is the target of the INSERT, UPDATE, or DELETE. Each element can be any column expression. `Table` objects will be expanded into their individual columns.

    Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.

    Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using `fetchone()` and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.

    Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

  `values`(*args, **kwargs)
    inherited from the `values()` method of `ValuesBase`

    specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.

    Note that the `Insert` and `Update` constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed to `Connection.execute()`. However, the `ValuesBase.values()` method can be used to “fix” a particular set of parameters into the statement.

    Multiple calls to `ValuesBase.values()` will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.

    - Parameters: | **kwargs – key value pairs representing the string key of a `Column` mapped to the value to be rendered into the VALUES or SET clause:
          users.insert().values(name="some name")

          users.update().where(users.c.id==5).values(name="some name")
    - *args – Alternatively, a dictionary, tuple or list of dictionaries or tuples can be passed as a single positional argument in order to form the VALUES or SET clause of the statement. The single dictionary form works the same as the kwargs form:
          users.insert().values({"name": "some name"})
      If a tuple is passed, the tuple should contain the same number of columns as the target `Table`:
          users.insert().values((5, "some name"))
      The `Insert` construct also supports multiply-rendered VALUES construct, for those backends which support this SQL syntax (SQLite, Postgresql, MySQL). This mode is indicated by passing a list of one or more dictionaries/tuples:
          users.insert().values([
                              {"name": "some name"},
                              {"name": "some other name"},
                              {"name": "yet another name"},
                          ])
      In the case of an `Update` construct, only the single dictionary/tuple form is accepted, else an exception is raised. It is also an exception case to attempt to mix the single-/multiple- value styles together, either through multiple `ValuesBase.values()` calls or by sending a list + kwargs at the same time. Note Passing a multiple values list is not the same as passing a multiple values list to the `Connection.execute()` method. Passing a list of parameter sets to `ValuesBase.values()` produces a construct of this form:
          INSERT INTO table (col1, col2, col3) VALUES
                          (col1_0, col2_0, col3_0),
                          (col1_1, col2_1, col3_1),
                          ...
    whereas a multiple list passed to `Connection.execute()` has the effect of using the DBAPI executemany() method, which provides a high-performance system of invoking a single-row INSERT statement many times against a series of parameter sets. The “executemany” style is supported by all database backends, as it does not depend on a special SQL syntax. New in version 0.8: Support for multiple-VALUES INSERT statements.

    See also

    Inserts, Updates and Deletes - SQL Expression Language Tutorial

    `insert()` - produce an `INSERT` statement

    `update()` - produce an `UPDATE` statement

  `with_hint`(text, selectable=None, dialect_name='*')
    inherited from the `with_hint()` method of `UpdateBase`

    Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.

    Note

    `UpdateBase.with_hint()` currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use `UpdateBase.prefix_with()`.

    The text of the hint is rendered in the appropriate location for the database backend in use, relative to the `Table` that is the subject of this statement, or optionally to that of the given `Table` passed as the `selectable` argument.

    The `dialect_name` option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:

        mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")

    New in version 0.7.6.

    Parameters: | text – Text of the hint. selectable – optional `Table` that specifies an element of the FROM clause within an UPDATE or DELETE to be the subject of the hint - applies only to certain backends. dialect_name – defaults to `*`, if specified as the name of a particular dialect, will apply these hints only when that dialect is in use.

class `sqlalchemy.sql.expression.``Join`(left, right, onclause=None, isouter=False)

  Bases: `sqlalchemy.sql.expression.FromClause`

  represent a `JOIN` construct between two `FromClause` elements.

  The public constructor function for `Join` is the module-level `join()` function, as well as the `join()` method available off all `FromClause` subclasses.

  `__init__`(left, right, onclause=None, isouter=False)

    Construct a new `Join`.

    The usual entrypoint here is the `join()` function or the `FromClause.join()` method of any `FromClause` object.

  `alias`(name=None)

    return an alias of this `Join`.

    Used against a `Join` object, `alias()` calls the `select()` method first so that a subquery against a `select()` construct is generated. the `select()` construct also has the `correlate` flag set to `False` and will not auto-correlate inside an enclosing `select()` construct.

    The equivalent long-hand form, given a `Join` object `j`, is:

        from sqlalchemy import select, alias
        j = alias(
            select([j.left, j.right]).\
                select_from(j).\
                with_labels(True).\
                correlate(False),
            name=name
        )

    See `alias()` for further details on aliases.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `join`(right, onclause=None, isouter=False)
    inherited from the `join()` method of `FromClause`

    return a join of this `FromClause` against another `FromClause`.

  `outerjoin`(right, onclause=None)
    inherited from the `outerjoin()` method of `FromClause`

    return an outer join of this `FromClause` against another `FromClause`.

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **kwargs)

    Create a `Select` from this `Join`.

    The equivalent long-hand form, given a `Join` object `j`, is:

        from sqlalchemy import select
        j = select([j.left, j.right], **kw).\
                    where(whereclause).\
                    select_from(j)

    Parameters: | whereclause – the WHERE criterion that will be sent to the `select()` function **kwargs – all other kwargs are sent to the underlying `select()` function.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

class `sqlalchemy.sql.operators.``Operators`

  Base of comparison and logical operators.

  Implements base methods `operate()` and `reverse_operate()`, as well as `__and__()`, `__or__()`, `__invert__()`.

  Usually is used via its most common subclass `ColumnOperators`.

  `__and__`(other)

    Implement the `&` operator.

    When used with SQL expressions, results in an AND operation, equivalent to `and_()`, that is:

        a & b

    is equivalent to:

        from sqlalchemy import and_
        and_(a, b)

    Care should be taken when using `&` regarding operator precedence; the `&` operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:

        (a == 2) & (b == 4)

  `__invert__`()

    Implement the `~` operator.

    When used with SQL expressions, results in a NOT operation, equivalent to `not_()`, that is:

        ~a

    is equivalent to:

        from sqlalchemy import not_
        not_(a)

  `__or__`(other)

    Implement the `|` operator.

    When used with SQL expressions, results in an OR operation, equivalent to `or_()`, that is:

        a | b

    is equivalent to:

        from sqlalchemy import or_
        or_(a, b)

    Care should be taken when using `|` regarding operator precedence; the `|` operator has the highest precedence. The operands should be enclosed in parenthesis if they contain further sub expressions:

        (a == 2) | (b == 4)

  `__weakref__`

    list of weak references to the object (if defined)

  `op`(opstring, precedence=0)

    produce a generic operator function.

    e.g.:

        somecolumn.op("*")(5)

    produces:

        somecolumn * 5

    This function can also be used to make bitwise operators explicit. For example:

        somecolumn.op('&')(0xff)

    is a bitwise AND of the value in `somecolumn`.

    Parameters: | operator – a string which will be output as the infix operator between this element and the expression passed to the generated function. precedence – precedence to apply to the operator, when parenthesizing expressions. A lower number will cause the expression to be parenthesized when applied against another operator with higher precedence. The default value of `0` is lower than all operators except for the comma (`,`) and `AS` operators. A value of 100 will be higher or equal to all operators, and -100 will be lower than or equal to all operators. New in version 0.8: - added the ‘precedence’ argument.

    See also

    Redefining and Creating New Operators

  `operate`(op, *other, **kwargs)

    Operate on an argument.

    This is the lowest level of operation, raises `NotImplementedError` by default.

    Overriding this on a subclass can allow common behavior to be applied to all operations. For example, overriding `ColumnOperators` to apply `func.lower()` to the left and right side:

        class MyComparator(ColumnOperators):
            def operate(self, op, other):
                return op(func.lower(self), func.lower(other))

    Parameters: | op – Operator callable. *other – the ‘other’ side of the operation. Will be a single scalar for most operations. **kwargs – modifiers. These may be passed by special operators such as `ColumnOperators.contains()`.

  `reverse_operate`(op, other, **kwargs)

    Reverse operate on an argument.

    Usage is the same as `operate()`.

class `sqlalchemy.sql.expression.``Select`(columns, whereclause=None, from_obj=None, distinct=False, having=None, correlate=True, prefixes=None, **kwargs)

  Bases: `sqlalchemy.sql.expression.HasPrefixes`, `sqlalchemy.sql.expression.SelectBase`

  Represents a `SELECT` statement.

  See also

  `select()` - the function which creates a `Select` object.

  Selecting - Core Tutorial description of `select()`.

  `__init__`(columns, whereclause=None, from_obj=None, distinct=False, having=None, correlate=True, prefixes=None, **kwargs)

    Construct a Select object.

    The public constructor for Select is the `select()` function; see that function for argument descriptions.

    Additional generative and mutator methods are available on the `SelectBase` superclass.

  `alias`(name=None)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `append_column`(column)

    append the given column expression to the columns clause of this select() construct.

    This is an in-place mutation method; the `column()` method is preferred, as it provides standard method chaining.

  `append_correlation`(fromclause)

    append the given correlation expression to this select() construct.

    This is an in-place mutation method; the `correlate()` method is preferred, as it provides standard method chaining.

  `append_from`(fromclause)

    append the given FromClause expression to this select() construct’s FROM clause.

    This is an in-place mutation method; the `select_from()` method is preferred, as it provides standard method chaining.

  `append_group_by`(*clauses)
    inherited from the `append_group_by()` method of `SelectBase`

    Append the given GROUP BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing GROUP BY criterion.

    This is an in-place mutation method; the `group_by()` method is preferred, as it provides standard method chaining.

  `append_having`(having)

    append the given expression to this select() construct’s HAVING criterion.

    The expression will be joined to existing HAVING criterion via AND.

    This is an in-place mutation method; the `having()` method is preferred, as it provides standard method chaining.

  `append_order_by`(*clauses)
    inherited from the `append_order_by()` method of `SelectBase`

    Append the given ORDER BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing ORDER BY criterion.

    This is an in-place mutation method; the `order_by()` method is preferred, as it provides standard method chaining.

  `append_prefix`(clause)

    append the given columns clause prefix expression to this select() construct.

    This is an in-place mutation method; the `prefix_with()` method is preferred, as it provides standard method chaining.

  `append_whereclause`(whereclause)

    append the given expression to this select() construct’s WHERE criterion.

    The expression will be joined to existing WHERE criterion via AND.

    This is an in-place mutation method; the `where()` method is preferred, as it provides standard method chaining.

  `apply_labels`()
    inherited from the `apply_labels()` method of `SelectBase`

    return a new selectable with the ‘use_labels’ flag set to True.

    This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.

  `as_scalar`()
    inherited from the `as_scalar()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, which can be used as a column expression.

    Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.

    The returned object is an instance of `ScalarSelect`.

  `autocommit`()
    inherited from the `autocommit()` method of `SelectBase`

    return a new selectable with the ‘autocommit’ flag set to

    Deprecated since version 0.6: `autocommit()` is deprecated. Use `Executable.execution_options()` with the ‘autocommit’ flag.

    True.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `column`(column)

    return a new select() construct with the given column expression added to its columns clause.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `correlate`(*fromclauses)

    return a new `Select` which will correlate the given FROM clauses to that of an enclosing `Select`.

    Calling this method turns off the `Select` object’s default behavior of “auto-correlation”. Normally, FROM elements which appear in a `Select` that encloses this one via its WHERE clause, ORDER BY, HAVING or columns clause will be omitted from this `Select` object’s FROM clause. Setting an explicit correlation collection using the `Select.correlate()` method provides a fixed list of FROM objects that can potentially take place in this process.

    When `Select.correlate()` is used to apply specific FROM clauses for correlation, the FROM elements become candidates for correlation regardless of how deeply nested this `Select` object is, relative to an enclosing `Select` which refers to the same FROM object. This is in contrast to the behavior of “auto-correlation” which only correlates to an immediate enclosing `Select`. Multi-level correlation ensures that the link between enclosed and enclosing `Select` is always via at least one WHERE/ORDER BY/HAVING/columns clause in order for correlation to take place.

    If `None` is passed, the `Select` object will correlate none of its FROM entries, and all will render unconditionally in the local FROM clause.

    Parameters: | *fromclauses – a list of one or more `FromClause` constructs, or other compatible constructs (i.e. ORM-mapped classes) to become part of the correlate collection. Changed in version 0.8.0: ORM-mapped classes are accepted by `Select.correlate()`.

    Changed in version 0.8.0: The `Select.correlate()` method no longer unconditionally removes entries from the FROM clause; instead, the candidate FROM entries must also be matched by a FROM entry located in an enclosing `Select`, which ultimately encloses this one as present in the WHERE clause, ORDER BY clause, HAVING clause, or columns clause of an enclosing `Select()`.

    Changed in version 0.8.2: explicit correlation takes place via any level of nesting of `Select` objects; in previous 0.8 versions, correlation would only occur relative to the immediate enclosing `Select` construct.

    See also

    `Select.correlate_except()`

    Correlated Subqueries

  `correlate_except`(*fromclauses)

    return a new `Select` which will omit the given FROM clauses from the auto-correlation process.

    Calling `Select.correlate_except()` turns off the `Select` object’s default behavior of “auto-correlation” for the given FROM elements. An element specified here will unconditionally appear in the FROM list, while all other FROM elements remain subject to normal auto-correlation behaviors.

    Changed in version 0.8.2: The `Select.correlate_except()` method was improved to fully prevent FROM clauses specified here from being omitted from the immediate FROM clause of this `Select`.

    If `None` is passed, the `Select` object will correlate all of its FROM entries.

    Changed in version 0.8.2: calling `correlate_except(None)` will correctly auto-correlate all FROM clauses.

    Parameters: | *fromclauses – a list of one or more `FromClause` constructs, or other compatible constructs (i.e. ORM-mapped classes) to become part of the correlate-exception collection.

    See also

    `Select.correlate()`

    Correlated Subqueries

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)
    inherited from the `count()` method of `FromClause`

    return a SELECT COUNT generated against this `FromClause`.

  `cte`(name=None, recursive=False)
    inherited from the `cte()` method of `SelectBase`

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    New in version 0.7.6.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples illustrate two examples from Postgresql’s documentation at http://www.postgresql.org/docs/8.4/static/queries-with.html.

    Example 1, non recursive:

        from sqlalchemy import Table, Column, String, Integer, MetaData, \
            select, func

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import Table, Column, String, Integer, MetaData, \
            select, func

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.part,
                parts_alias.c.sub_part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).                    select_from(included_parts.join(parts,
                            included_parts.c.part==parts.c.part)).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    See also

    `orm.query.Query.cte()` - ORM version of `SelectBase.cte()`.

  `description`
    inherited from the `description` attribute of `FromClause`

    a brief description of this FromClause.

    Used primarily for error message formatting.

  `distinct`(*expr)

    Return a new select() construct which will apply DISTINCT to its columns clause.

    Parameters: | *expr – optional column expressions. When present, the Postgresql dialect will render a `DISTINCT ON (<expressions>>)` construct.

  `except_`(other, **kwargs)

    return a SQL EXCEPT of this select() construct against the given selectable.

  `except_all`(other, **kwargs)

    return a SQL EXCEPT ALL of this select() construct against the given selectable.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `froms`

    Return the displayed list of FromClause elements.

  `get_children`(column_collections=True, **kwargs)

    return child elements as per the ClauseElement specification.

  `group_by`(*clauses)
    inherited from the `group_by()` method of `SelectBase`

    return a new selectable with the given list of GROUP BY criterion applied.

    The criterion will be appended to any pre-existing GROUP BY criterion.

  `having`(having)

    return a new select() construct with the given expression added to its HAVING clause, joined to the existing clause via AND, if any.

  `inner_columns`

    an iterator of all ColumnElement expressions which would be rendered into the columns clause of the resulting SELECT statement.

  `intersect`(other, **kwargs)

    return a SQL INTERSECT of this select() construct against the given selectable.

  `intersect_all`(other, **kwargs)

    return a SQL INTERSECT ALL of this select() construct against the given selectable.

  `join`(right, onclause=None, isouter=False)
    inherited from the `join()` method of `FromClause`

    return a join of this `FromClause` against another `FromClause`.

  `label`(name)
    inherited from the `label()` method of `SelectBase`

    return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.

    See also

    `as_scalar()`.

  `limit`(limit)
    inherited from the `limit()` method of `SelectBase`

    return a new selectable with the given LIMIT criterion applied.

  `locate_all_froms`

    return a Set of all FromClause elements referenced by this Select.

    This set is a superset of that returned by the `froms` property, which is specifically for those FromClause elements that would actually be rendered.

  `offset`(offset)
    inherited from the `offset()` method of `SelectBase`

    return a new selectable with the given OFFSET criterion applied.

  `order_by`(*clauses)
    inherited from the `order_by()` method of `SelectBase`

    return a new selectable with the given list of ORDER BY criterion applied.

    The criterion will be appended to any pre-existing ORDER BY criterion.

  `outerjoin`(right, onclause=None)
    inherited from the `outerjoin()` method of `FromClause`

    return an outer join of this `FromClause` against another `FromClause`.

  `params`(*optionaldict, **kwargs)
    inherited from the `params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Returns a copy of this ClauseElement with `bindparam()` elements replaced with values taken from the given dictionary:

        >>> clause = column('x') + bindparam('foo')
        >>> print clause.compile().params
        {'foo':None}
        >>> print clause.params({'foo':7}).compile().params
        {'foo':7}

  `prefix_with`(*expr, **kw)
    inherited from the `prefix_with()` method of `HasPrefixes`

    Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.

    This is used to support backend-specific prefix keywords such as those provided by MySQL.

    E.g.:

        stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")

    Multiple prefixes can be specified by multiple calls to `prefix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the INSERT, UPDATE, or DELETE keyword. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this prefix to only that dialect.

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `reduce_columns`(only_synonyms=True)

    Return a new :func`.select` construct with redundantly named, equivalently-valued columns removed from the columns clause.

    “Redundant” here means two columns where one refers to the other either based on foreign key, or via a simple equality comparison in the WHERE clause of the statement. The primary purpose of this method is to automatically construct a select statement with all uniquely-named columns, without the need to use table-qualified labels as `apply_labels()` does.

    When columns are omitted based on foreign key, the referred-to column is the one that’s kept. When columns are omitted based on WHERE eqivalence, the first column in the columns clause is the one that’s kept.

    Parameters: | only_synonyms – when True, limit the removal of columns to those which have the same name as the equivalent. Otherwise, all columns that are equivalent to another are removed.

    New in version 0.8.

  `replace_selectable`(old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `select_from`(fromclause)

    return a new `select()` construct with the given FROM expression merged into its list of FROM objects.

    E.g.:

        table1 = table('t1', column('a'))
        table2 = table('t2', column('b'))
        s = select([table1.c.a]).\
            select_from(
                table1.join(table2, table1.c.a==table2.c.b)
            )

    The “from” list is a unique set on the identity of each element, so adding an already present `Table` or other selectable will have no effect. Passing a `Join` that refers to an already present `Table` or other selectable will have the effect of concealing the presence of that selectable as an individual element in the rendered FROM list, instead rendering it into a JOIN clause.

    While the typical purpose of `Select.select_from()` is to replace the default, derived FROM clause with a join, it can also be called with individual table elements, multiple times if desired, in the case that the FROM clause cannot be fully derived from the columns clause:

        select([func.count('*')]).select_from(table1)

  `self_group`(against=None)

    return a ‘grouping’ construct as per the ClauseElement specification.

    This produces an element that can be embedded in an expression. Note that this method is called automatically as needed when constructing expressions and should not require explicit use.

  `union`(other, **kwargs)

    return a SQL UNION of this select() construct against the given selectable.

  `union_all`(other, **kwargs)

    return a SQL UNION ALL of this select() construct against the given selectable.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

  `where`(whereclause)

    return a new select() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.

  `with_hint`(selectable, text, dialect_name='*')

    Add an indexing hint for the given selectable to this `Select`.

    The text of the hint is rendered in the appropriate location for the database backend in use, relative to the given `Table` or `Alias` passed as the `selectable` argument. The dialect implementation typically uses Python string substitution syntax with the token `%(name)s` to render the name of the table or alias. E.g. when using Oracle, the following:

        select([mytable]).\
            with_hint(mytable, "+ index(%(name)s ix_mytable)")

    Would render SQL as:

        select /*+ index(mytable ix_mytable) */ ... from mytable

    The `dialect_name` option will limit the rendering of a particular hint to a particular backend. Such as, to add hints for both Oracle and Sybase simultaneously:

        select([mytable]).\
            with_hint(mytable, "+ index(%(name)s ix_mytable)", 'oracle').\
            with_hint(mytable, "WITH INDEX ix_mytable", 'sybase')

  `with_only_columns`(columns)

    Return a new `select()` construct with its columns clause replaced with the given columns.

    Changed in version 0.7.3: Due to a bug fix, this method has a slight behavioral change as of version 0.7.3. Prior to version 0.7.3, the FROM clause of a `select()` was calculated upfront and as new columns were added; in 0.7.3 and later it’s calculated at compile time, fixing an issue regarding late binding of columns to parent tables. This changes the behavior of `Select.with_only_columns()` in that FROM clauses no longer represented in the new list are dropped, but this behavior is more consistent in that the FROM clauses are consistently derived from the current columns clause. The original intent of this method is to allow trimming of the existing columns list to be fewer columns than originally present; the use case of replacing the columns list with an entirely different one hadn’t been anticipated until 0.7.3 was released; the usage guidelines below illustrate how this should be done.

    This method is exactly equivalent to as if the original `select()` had been called with the given columns clause. I.e. a statement:

        s = select([table1.c.a, table1.c.b])
        s = s.with_only_columns([table1.c.b])

    should be exactly equivalent to:

        s = select([table1.c.b])

    This means that FROM clauses which are only derived from the column list will be discarded if the new column list no longer contains that FROM:

        >>> table1 = table('t1', column('a'), column('b'))
        >>> table2 = table('t2', column('a'), column('b'))
        >>> s1 = select([table1.c.a, table2.c.b])
        >>> print s1
        SELECT t1.a, t2.b FROM t1, t2
        >>> s2 = s1.with_only_columns([table2.c.b])
        >>> print s2
        SELECT t2.b FROM t1

    The preferred way to maintain a specific FROM clause in the construct, assuming it won’t be represented anywhere else (i.e. not in the WHERE clause, etc.) is to set it using `Select.select_from()`:

        >>> s1 = select([table1.c.a, table2.c.b]).\
        ...         select_from(table1.join(table2,
        ...                 table1.c.a==table2.c.a))
        >>> s2 = s1.with_only_columns([table2.c.b])
        >>> print s2
        SELECT t2.b FROM t1 JOIN t2 ON t1.a=t2.a

    Care should also be taken to use the correct set of column objects passed to `Select.with_only_columns()`. Since the method is essentially equivalent to calling the `select()` construct in the first place with the given columns, the columns passed to `Select.with_only_columns()` should usually be a subset of those which were passed to the `select()` construct, not those which are available from the `.c` collection of that `select()`. That is:

        s = select([table1.c.a, table1.c.b]).select_from(table1)
        s = s.with_only_columns([table1.c.b])

    and not:

        # usually incorrect
        s = s.with_only_columns([s.c.b])

    The latter would produce the SQL:

        SELECT b
        FROM (SELECT t1.a AS a, t1.b AS b
        FROM t1), t1

    Since the `select()` construct is essentially being asked to select both from `table1` as well as itself.

class `sqlalchemy.sql.expression.``Selectable`

  Bases: `sqlalchemy.sql.expression.ClauseElement`

  mark a class as being selectable

class `sqlalchemy.sql.expression.``SelectBase`(use_labels=False, for_update=False, limit=None, offset=None, order_by=None, group_by=None, bind=None, autocommit=None)

  Bases: `sqlalchemy.sql.expression.Executable`, `sqlalchemy.sql.expression.FromClause`

  Base class for `Select` and `CompoundSelects`.

  `append_group_by`(*clauses)

    Append the given GROUP BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing GROUP BY criterion.

    This is an in-place mutation method; the `group_by()` method is preferred, as it provides standard method chaining.

  `append_order_by`(*clauses)

    Append the given ORDER BY criterion applied to this selectable.

    The criterion will be appended to any pre-existing ORDER BY criterion.

    This is an in-place mutation method; the `order_by()` method is preferred, as it provides standard method chaining.

  `apply_labels`()

    return a new selectable with the ‘use_labels’ flag set to True.

    This will result in column expressions being generated using labels against their table name, such as “SELECT somecolumn AS tablename_somecolumn”. This allows selectables which contain multiple FROM clauses to produce a unique set of column names regardless of name conflicts among the individual FROM clauses.

  `as_scalar`()

    return a ‘scalar’ representation of this selectable, which can be used as a column expression.

    Typically, a select statement which has only one column in its columns clause is eligible to be used as a scalar expression.

    The returned object is an instance of `ScalarSelect`.

  `autocommit`()

    return a new selectable with the ‘autocommit’ flag set to

    Deprecated since version 0.6: `autocommit()` is deprecated. Use `Executable.execution_options()` with the ‘autocommit’ flag.

    True.

  `cte`(name=None, recursive=False)

    Return a new `CTE`, or Common Table Expression instance.

    Common table expressions are a SQL standard whereby SELECT statements can draw upon secondary statements specified along with the primary statement, using a clause called “WITH”. Special semantics regarding UNION can also be employed to allow “recursive” queries, where a SELECT statement can draw upon the set of rows that have previously been selected.

    SQLAlchemy detects `CTE` objects, which are treated similarly to `Alias` objects, as special elements to be delivered to the FROM clause of the statement as well as to a WITH clause at the top of the statement.

    New in version 0.7.6.

    Parameters: | name – name given to the common table expression. Like `_FromClause.alias()`, the name can be left as `None` in which case an anonymous symbol will be used at query compile time. recursive – if `True`, will render `WITH RECURSIVE`. A recursive common table expression is intended to be used in conjunction with UNION ALL in order to derive rows from those already selected.

    The following examples illustrate two examples from Postgresql’s documentation at http://www.postgresql.org/docs/8.4/static/queries-with.html.

    Example 1, non recursive:

        from sqlalchemy import Table, Column, String, Integer, MetaData, \
            select, func

        metadata = MetaData()

        orders = Table('orders', metadata,
            Column('region', String),
            Column('amount', Integer),
            Column('product', String),
            Column('quantity', Integer)
        )

        regional_sales = select([
                            orders.c.region,
                            func.sum(orders.c.amount).label('total_sales')
                        ]).group_by(orders.c.region).cte("regional_sales")

        top_regions = select([regional_sales.c.region]).\
                where(
                    regional_sales.c.total_sales >
                    select([
                        func.sum(regional_sales.c.total_sales)/10
                    ])
                ).cte("top_regions")

        statement = select([
                    orders.c.region,
                    orders.c.product,
                    func.sum(orders.c.quantity).label("product_units"),
                    func.sum(orders.c.amount).label("product_sales")
            ]).where(orders.c.region.in_(
                select([top_regions.c.region])
            )).group_by(orders.c.region, orders.c.product)

        result = conn.execute(statement).fetchall()

    Example 2, WITH RECURSIVE:

        from sqlalchemy import Table, Column, String, Integer, MetaData, \
            select, func

        metadata = MetaData()

        parts = Table('parts', metadata,
            Column('part', String),
            Column('sub_part', String),
            Column('quantity', Integer),
        )

        included_parts = select([
                            parts.c.sub_part,
                            parts.c.part,
                            parts.c.quantity]).\
                            where(parts.c.part=='our part').\
                            cte(recursive=True)

        incl_alias = included_parts.alias()
        parts_alias = parts.alias()
        included_parts = included_parts.union_all(
            select([
                parts_alias.c.part,
                parts_alias.c.sub_part,
                parts_alias.c.quantity
            ]).
                where(parts_alias.c.part==incl_alias.c.sub_part)
        )

        statement = select([
                    included_parts.c.sub_part,
                    func.sum(included_parts.c.quantity).
                      label('total_quantity')
                ]).                    select_from(included_parts.join(parts,
                            included_parts.c.part==parts.c.part)).\
                group_by(included_parts.c.sub_part)

        result = conn.execute(statement).fetchall()

    See also

    `orm.query.Query.cte()` - ORM version of `SelectBase.cte()`.

  `group_by`(*clauses)

    return a new selectable with the given list of GROUP BY criterion applied.

    The criterion will be appended to any pre-existing GROUP BY criterion.

  `label`(name)

    return a ‘scalar’ representation of this selectable, embedded as a subquery with a label.

    See also

    `as_scalar()`.

  `limit`(limit)

    return a new selectable with the given LIMIT criterion applied.

  `offset`(offset)

    return a new selectable with the given OFFSET criterion applied.

  `order_by`(*clauses)

    return a new selectable with the given list of ORDER BY criterion applied.

    The criterion will be appended to any pre-existing ORDER BY criterion.

class `sqlalchemy.sql.expression.``TableClause`(name, *columns)

  Bases: `sqlalchemy.sql.expression.Immutable`, `sqlalchemy.sql.expression.FromClause`

  Represents a minimal “table” construct.

  The constructor for `TableClause` is the `table()` function. This produces a lightweight table object that has only a name and a collection of columns, which are typically produced by the `column()` function:

      from sqlalchemy.sql import table, column

      user = table("user",
              column("id"),
              column("name"),
              column("description"),
      )

  The `TableClause` construct serves as the base for the more commonly used `Table` object, providing the usual set of `FromClause` services including the `.c.` collection and statement generation methods.

  It does not provide all the additional schema-level services of `Table`, including constraints, references to other tables, or support for `MetaData`-level services. It’s useful on its own as an ad-hoc construct used to generate quick SQL statements when a more fully fledged `Table` is not on hand.

  `alias`(name=None)
    inherited from the `alias()` method of `FromClause`

    return an alias of this `FromClause`.

    This is shorthand for calling:

        from sqlalchemy import alias
        a = alias(self, name=name)

    See `alias()` for details.

  `c`
    inherited from the `c` attribute of `FromClause`

    An alias for the `columns` attribute.

  `columns`
    inherited from the `columns` attribute of `FromClause`

    A named-based collection of `ColumnElement` objects maintained by this `FromClause`.

    The `columns`, or `c` collection, is the gateway to the construction of SQL expressions using table-bound or other selectable-bound columns:

        select([mytable]).where(mytable.c.somecolumn == 5)

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `correspond_on_equivalents`(column, equivalents)
    inherited from the `correspond_on_equivalents()` method of `FromClause`

    Return corresponding_column for the given column, or if None search for a match in the given dictionary.

  `corresponding_column`(column, require_embedded=False)
    inherited from the `corresponding_column()` method of `FromClause`

    Given a `ColumnElement`, return the exported `ColumnElement` object from this `Selectable` which corresponds to that original `Column` via a common ancestor column.

    Parameters: | column – the target `ColumnElement` to be matched require_embedded – only return corresponding columns for

    the given `ColumnElement`, if the given `ColumnElement` is actually present within a sub-element of this `FromClause`. Normally the column will match if it merely shares a common ancestor with one of the exported columns of this `FromClause`.

  `count`(whereclause=None, **params)

    return a SELECT COUNT generated against this `TableClause`.

  `delete`(whereclause=None, **kwargs)

    Generate a `delete()` construct against this `TableClause`.

    E.g.:

        table.delete().where(table.c.id==7)

    See `delete()` for argument and usage information.

  `foreign_keys`
    inherited from the `foreign_keys` attribute of `FromClause`

    Return the collection of ForeignKey objects which this FromClause references.

  `implicit_returning` = False

    `TableClause` doesn’t support having a primary key or column -level defaults, so implicit returning doesn’t apply.

  `insert`(values=None, inline=False, **kwargs)

    Generate an `insert()` construct against this `TableClause`.

    E.g.:

        table.insert().values(name='foo')

    See `insert()` for argument and usage information.

  `is_derived_from`(fromclause)
    inherited from the `is_derived_from()` method of `FromClause`

    Return True if this FromClause is ‘derived’ from the given FromClause.

    An example would be an Alias of a Table is derived from that Table.

  `join`(right, onclause=None, isouter=False)
    inherited from the `join()` method of `FromClause`

    return a join of this `FromClause` against another `FromClause`.

  `outerjoin`(right, onclause=None)
    inherited from the `outerjoin()` method of `FromClause`

    return an outer join of this `FromClause` against another `FromClause`.

  `primary_key`
    inherited from the `primary_key` attribute of `FromClause`

    Return the collection of Column objects which comprise the primary key of this FromClause.

  `replace_selectable`(old, alias)
    inherited from the `replace_selectable()` method of `FromClause`

    replace all occurrences of FromClause ‘old’ with the given Alias object, returning a copy of this `FromClause`.

  `select`(whereclause=None, **params)
    inherited from the `select()` method of `FromClause`

    return a SELECT of this `FromClause`.

    See also

    `select()` - general purpose method which allows for arbitrary column lists.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `update`(whereclause=None, values=None, inline=False, **kwargs)

    Generate an `update()` construct against this `TableClause`.

    E.g.:

        table.update().where(table.c.id==7).values(name='foo')

    See `update()` for argument and usage information.

class `sqlalchemy.sql.expression.``UnaryExpression`(element, operator=None, modifier=None, type_=None, negate=None)

  Bases: `sqlalchemy.sql.expression.ColumnElement`

  Define a ‘unary’ expression.

  A unary expression has a single column expression and an operator. The operator can be placed on the left (where it is called the ‘operator’) or right (where it is called the ‘modifier’) of the column expression.

  `compare`(other, **kw)

    Compare this `UnaryExpression` against the given `ClauseElement`.

class `sqlalchemy.sql.expression.``Update`(table, whereclause, values=None, inline=False, bind=None, prefixes=None, returning=None, **kwargs)

  Bases: `sqlalchemy.sql.expression.ValuesBase`

  Represent an Update construct.

  The `Update` object is created using the `update()` function.

  `bind`
    inherited from the `bind` attribute of `UpdateBase`

    Return a ‘bind’ linked to this `UpdateBase` or a `Table` associated with it.

  `compare`(other, **kw)
    inherited from the `compare()` method of `ClauseElement`

    Compare this ClauseElement to the given ClauseElement.

    Subclasses should override the default behavior, which is a straight identity comparison.

    **kw are arguments consumed by subclass compare() methods and may be used to modify the criteria for comparison. (see `ColumnElement`)

  `compile`(bind=None, dialect=None, **kw)
    inherited from the `compile()` method of `ClauseElement`

    Compile this SQL expression.

    The return value is a `Compiled` object. Calling `str()` or `unicode()` on the returned value will yield a string representation of the result. The `Compiled` object also can return a dictionary of bind parameter names and values using the `params` accessor.

    Parameters: | bind – An `Engine` or `Connection` from which a `Compiled` will be acquired. This argument takes precedence over this `ClauseElement`‘s bound engine, if any. column_keys – Used for INSERT and UPDATE statements, a list of column names which should be present in the VALUES clause of the compiled statement. If `None`, all columns from the target table object are rendered. dialect – A `Dialect` instance from which a `Compiled` will be acquired. This argument takes precedence over the bind argument as well as this `ClauseElement`‘s bound engine, if any. inline – Used for INSERT statements, for a dialect which does not support inline retrieval of newly generated primary key columns, will force the expression used to create the new primary key value to be rendered inline within the INSERT statement’s VALUES clause. This typically refers to Sequence execution but may also refer to any server-side default generation function associated with a primary key Column.

  `execute`(*multiparams, **params)
    inherited from the `execute()` method of `Executable`

    Compile and execute this `Executable`.

  `execution_options`(**kw)
    inherited from the `execution_options()` method of `Executable`

    Set non-SQL options for the statement which take effect during execution.

    Execution options can be set on a per-statement or per `Connection` basis. Additionally, the `Engine` and ORM `Query` objects provide access to execution options which they in turn configure upon connections.

    The `execution_options()` method is generative. A new instance of this statement is returned that contains the options:

        statement = select([table.c.x, table.c.y])
        statement = statement.execution_options(autocommit=True)

    Note that only a subset of possible execution options can be applied to a statement - these include “autocommit” and “stream_results”, but not “isolation_level” or “compiled_cache”. See `Connection.execution_options()` for a full list of possible options.

    See also

    `Connection.execution_options()`

    `Query.execution_options()`

  `params`(*arg, **kw)
    inherited from the `params()` method of `UpdateBase`

    Set the parameters for the statement.

    This method raises `NotImplementedError` on the base class, and is overridden by `ValuesBase` to provide the SET/VALUES clause of UPDATE and INSERT.

  `prefix_with`(*expr, **kw)
    inherited from the `prefix_with()` method of `HasPrefixes`

    Add one or more expressions following the statement keyword, i.e. SELECT, INSERT, UPDATE, or DELETE. Generative.

    This is used to support backend-specific prefix keywords such as those provided by MySQL.

    E.g.:

        stmt = table.insert().prefix_with("LOW_PRIORITY", dialect="mysql")

    Multiple prefixes can be specified by multiple calls to `prefix_with()`.

    Parameters: | *expr – textual or `ClauseElement` construct which will be rendered following the INSERT, UPDATE, or DELETE keyword. **kw – A single keyword ‘dialect’ is accepted. This is an optional string dialect name which will limit rendering of this prefix to only that dialect.

  `returning`(*cols)
    inherited from the `returning()` method of `UpdateBase`

    Add a RETURNING or equivalent clause to this statement.

    The given list of columns represent columns within the table that is the target of the INSERT, UPDATE, or DELETE. Each element can be any column expression. `Table` objects will be expanded into their individual columns.

    Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.

    Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using `fetchone()` and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.

    Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.

  `scalar`(*multiparams, **params)
    inherited from the `scalar()` method of `Executable`

    Compile and execute this `Executable`, returning the result’s scalar representation.

  `self_group`(against=None)
    inherited from the `self_group()` method of `ClauseElement`

    Apply a ‘grouping’ to this `ClauseElement`.

    This method is overridden by subclasses to return a “grouping” construct, i.e. parenthesis. In particular it’s used by “binary” expressions to provide a grouping around themselves when placed into a larger expression, as well as by `select()` constructs when placed into the FROM clause of another `select()`. (Note that subqueries should be normally created using the `Select.alias()` method, as many platforms require nested SELECT statements to be named).

    As expressions are composed together, the application of `self_group()` is automatic - end-user code should never need to use this method directly. Note that SQLAlchemy’s clause constructs take operator precedence into account - so parenthesis might not be needed, for example, in an expression like `x OR (y AND z)` - AND takes precedence over OR.

    The base `self_group()` method of `ClauseElement` just returns self.

  `unique_params`(*optionaldict, **kwargs)
    inherited from the `unique_params()` method of `ClauseElement`

    Return a copy with `bindparam()` elements replaced.

    Same functionality as `params()`, except adds unique=True to affected bind parameters so that multiple statements can be used.

  `values`(*args, **kwargs)
    inherited from the `values()` method of `ValuesBase`

    specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.

    Note that the `Insert` and `Update` constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed to `Connection.execute()`. However, the `ValuesBase.values()` method can be used to “fix” a particular set of parameters into the statement.

    Multiple calls to `ValuesBase.values()` will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.

    - Parameters: | **kwargs – key value pairs representing the string key of a `Column` mapped to the value to be rendered into the VALUES or SET clause:
          users.insert().values(name="some name")

          users.update().where(users.c.id==5).values(name="some name")
    - *args – Alternatively, a dictionary, tuple or list of dictionaries or tuples can be passed as a single positional argument in order to form the VALUES or SET clause of the statement. The single dictionary form works the same as the kwargs form:
          users.insert().values({"name": "some name"})
      If a tuple is passed, the tuple should contain the same number of columns as the target `Table`:
          users.insert().values((5, "some name"))
      The `Insert` construct also supports multiply-rendered VALUES construct, for those backends which support this SQL syntax (SQLite, Postgresql, MySQL). This mode is indicated by passing a list of one or more dictionaries/tuples:
          users.insert().values([
                              {"name": "some name"},
                              {"name": "some other name"},
                              {"name": "yet another name"},
                          ])
      In the case of an `Update` construct, only the single dictionary/tuple form is accepted, else an exception is raised. It is also an exception case to attempt to mix the single-/multiple- value styles together, either through multiple `ValuesBase.values()` calls or by sending a list + kwargs at the same time. Note Passing a multiple values list is not the same as passing a multiple values list to the `Connection.execute()` method. Passing a list of parameter sets to `ValuesBase.values()` produces a construct of this form:
          INSERT INTO table (col1, col2, col3) VALUES
                          (col1_0, col2_0, col3_0),
                          (col1_1, col2_1, col3_1),
                          ...
    whereas a multiple list passed to `Connection.execute()` has the effect of using the DBAPI executemany() method, which provides a high-performance system of invoking a single-row INSERT statement many times against a series of parameter sets. The “executemany” style is supported by all database backends, as it does not depend on a special SQL syntax. New in version 0.8: Support for multiple-VALUES INSERT statements.

    See also

    Inserts, Updates and Deletes - SQL Expression Language Tutorial

    `insert()` - produce an `INSERT` statement

    `update()` - produce an `UPDATE` statement

  `where`(whereclause)

    return a new update() construct with the given expression added to its WHERE clause, joined to the existing clause via AND, if any.

  `with_hint`(text, selectable=None, dialect_name='*')
    inherited from the `with_hint()` method of `UpdateBase`

    Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.

    Note

    `UpdateBase.with_hint()` currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use `UpdateBase.prefix_with()`.

    The text of the hint is rendered in the appropriate location for the database backend in use, relative to the `Table` that is the subject of this statement, or optionally to that of the given `Table` passed as the `selectable` argument.

    The `dialect_name` option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:

        mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")

    New in version 0.7.6.

    Parameters: | text – Text of the hint. selectable – optional `Table` that specifies an element of the FROM clause within an UPDATE or DELETE to be the subject of the hint - applies only to certain backends. dialect_name – defaults to `*`, if specified as the name of a particular dialect, will apply these hints only when that dialect is in use.

class `sqlalchemy.sql.expression.``UpdateBase`

  Bases: `sqlalchemy.sql.expression.HasPrefixes`, `sqlalchemy.sql.expression.Executable`, `sqlalchemy.sql.expression.ClauseElement`

  Form the base for `INSERT`, `UPDATE`, and `DELETE` statements.

  `bind`

    Return a ‘bind’ linked to this `UpdateBase` or a `Table` associated with it.

  `params`(*arg, **kw)

    Set the parameters for the statement.

    This method raises `NotImplementedError` on the base class, and is overridden by `ValuesBase` to provide the SET/VALUES clause of UPDATE and INSERT.

  `returning`(*cols)

    Add a RETURNING or equivalent clause to this statement.

    The given list of columns represent columns within the table that is the target of the INSERT, UPDATE, or DELETE. Each element can be any column expression. `Table` objects will be expanded into their individual columns.

    Upon compilation, a RETURNING clause, or database equivalent, will be rendered within the statement. For INSERT and UPDATE, the values are the newly inserted/updated values. For DELETE, the values are those of the rows which were deleted.

    Upon execution, the values of the columns to be returned are made available via the result set and can be iterated using `fetchone()` and similar. For DBAPIs which do not natively support returning values (i.e. cx_oracle), SQLAlchemy will approximate this behavior at the result level so that a reasonable amount of behavioral neutrality is provided.

    Note that not all databases/DBAPIs support RETURNING. For those backends with no support, an exception is raised upon compilation and/or execution. For those who do support it, the functionality across backends varies greatly, including restrictions on executemany() and other statements which return multiple rows. Please read the documentation notes for the database in use in order to determine the availability of RETURNING.

  `with_hint`(text, selectable=None, dialect_name='*')

    Add a table hint for a single table to this INSERT/UPDATE/DELETE statement.

    Note

    `UpdateBase.with_hint()` currently applies only to Microsoft SQL Server. For MySQL INSERT/UPDATE/DELETE hints, use `UpdateBase.prefix_with()`.

    The text of the hint is rendered in the appropriate location for the database backend in use, relative to the `Table` that is the subject of this statement, or optionally to that of the given `Table` passed as the `selectable` argument.

    The `dialect_name` option will limit the rendering of a particular hint to a particular backend. Such as, to add a hint that only takes effect for SQL Server:

        mytable.insert().with_hint("WITH (PAGLOCK)", dialect_name="mssql")

    New in version 0.7.6.

    Parameters: | text – Text of the hint. selectable – optional `Table` that specifies an element of the FROM clause within an UPDATE or DELETE to be the subject of the hint - applies only to certain backends. dialect_name – defaults to `*`, if specified as the name of a particular dialect, will apply these hints only when that dialect is in use.

class `sqlalchemy.sql.expression.``ValuesBase`(table, values, prefixes)

  Bases: `sqlalchemy.sql.expression.UpdateBase`

  Supplies support for `ValuesBase.values()` to INSERT and UPDATE constructs.

  `values`(*args, **kwargs)

    specify a fixed VALUES clause for an INSERT statement, or the SET clause for an UPDATE.

    Note that the `Insert` and `Update` constructs support per-execution time formatting of the VALUES and/or SET clauses, based on the arguments passed to `Connection.execute()`. However, the `ValuesBase.values()` method can be used to “fix” a particular set of parameters into the statement.

    Multiple calls to `ValuesBase.values()` will produce a new construct, each one with the parameter list modified to include the new parameters sent. In the typical case of a single dictionary of parameters, the newly passed keys will replace the same keys in the previous construct. In the case of a list-based “multiple values” construct, each new list of values is extended onto the existing list of values.

    - Parameters: | **kwargs – key value pairs representing the string key of a `Column` mapped to the value to be rendered into the VALUES or SET clause:
          users.insert().values(name="some name")

          users.update().where(users.c.id==5).values(name="some name")
    - *args – Alternatively, a dictionary, tuple or list of dictionaries or tuples can be passed as a single positional argument in order to form the VALUES or SET clause of the statement. The single dictionary form works the same as the kwargs form:
          users.insert().values({"name": "some name"})
      If a tuple is passed, the tuple should contain the same number of columns as the target `Table`:
          users.insert().values((5, "some name"))
      The `Insert` construct also supports multiply-rendered VALUES construct, for those backends which support this SQL syntax (SQLite, Postgresql, MySQL). This mode is indicated by passing a list of one or more dictionaries/tuples:
          users.insert().values([
                              {"name": "some name"},
                              {"name": "some other name"},
                              {"name": "yet another name"},
                          ])
      In the case of an `Update` construct, only the single dictionary/tuple form is accepted, else an exception is raised. It is also an exception case to attempt to mix the single-/multiple- value styles together, either through multiple `ValuesBase.values()` calls or by sending a list + kwargs at the same time. Note Passing a multiple values list is not the same as passing a multiple values list to the `Connection.execute()` method. Passing a list of parameter sets to `ValuesBase.values()` produces a construct of this form:
          INSERT INTO table (col1, col2, col3) VALUES
                          (col1_0, col2_0, col3_0),
                          (col1_1, col2_1, col3_1),
                          ...
    whereas a multiple list passed to `Connection.execute()` has the effect of using the DBAPI executemany() method, which provides a high-performance system of invoking a single-row INSERT statement many times against a series of parameter sets. The “executemany” style is supported by all database backends, as it does not depend on a special SQL syntax. New in version 0.8: Support for multiple-VALUES INSERT statements.

    See also

    Inserts, Updates and Deletes - SQL Expression Language Tutorial

    `insert()` - produce an `INSERT` statement

    `update()` - produce an `UPDATE` statement

## Generic Functions

SQL functions which are known to SQLAlchemy with regards to database-specific rendering, return types and argument behavior. Generic functions are invoked like all SQL functions, using the `func` attribute:

    select([func.count()]).select_from(sometable)

Note that any name not known to `func` generates the function name as is - there is no restriction on what SQL functions can be called, known or unknown to SQLAlchemy, built-in or user defined. The section here only describes those functions where SQLAlchemy already knows what argument and return types are in use.

class `sqlalchemy.sql.functions.``AnsiFunction`(**kwargs)

  Bases: `sqlalchemy.sql.functions.GenericFunction`

  `identifier` = 'AnsiFunction'
  `name` = 'AnsiFunction'

class `sqlalchemy.sql.functions.``GenericFunction`(*args, **kwargs)

  Bases: `sqlalchemy.sql.expression.Function`

  Define a ‘generic’ function.

  A generic function is a pre-established `Function` class that is instantiated automatically when called by name from the `func` attribute. Note that calling any name from `func` has the effect that a new `Function` instance is created automatically, given that name. The primary use case for defining a `GenericFunction` class is so that a function of a particular name may be given a fixed return type. It can also include custom argument parsing schemes as well as additional methods.

  Subclasses of `GenericFunction` are automatically registered under the name of the class. For example, a user-defined function `as_utc()` would be available immediately:

      from sqlalchemy.sql.functions import GenericFunction
      from sqlalchemy.types import DateTime

      class as_utc(GenericFunction):
          type = DateTime

      print select([func.as_utc()])

  User-defined generic functions can be organized into packages by specifying the “package” attribute when defining `GenericFunction`. Third party libraries containing many functions may want to use this in order to avoid name conflicts with other systems. For example, if our `as_utc()` function were part of a package “time”:

      class as_utc(GenericFunction):
          type = DateTime
          package = "time"

  The above function would be available from `func` using the package name `time`:

      print select([func.time.as_utc()])

  A final option is to allow the function to be accessed from one name in `func` but to render as a different name. The `identifier` attribute will override the name used to access the function as loaded from `func`, but will retain the usage of `name` as the rendered name:

      class GeoBuffer(GenericFunction):
          type = Geometry
          package = "geo"
          name = "ST_Buffer"
          identifier = "buffer"

  The above function will render as follows:

      >>> print func.geo.buffer()
      ST_Buffer()

  New in version 0.8: `GenericFunction` now supports automatic registration of new functions as well as package and custom naming support.

  Changed in version 0.8: The attribute name `type` is used to specify the function’s return type at the class level. Previously, the name `__return_type__` was used. This name is still recognized for backwards-compatibility.

  `coerce_arguments` = True
  `identifier` = 'GenericFunction'
  `name` = 'GenericFunction'

class `sqlalchemy.sql.functions.``ReturnTypeFromArgs`(*args, **kwargs)

  Bases: `sqlalchemy.sql.functions.GenericFunction`

  Define a function whose return type is the same as its arguments.

  `identifier` = 'ReturnTypeFromArgs'
  `name` = 'ReturnTypeFromArgs'

class `sqlalchemy.sql.functions.``char_length`(arg, **kwargs)

  Bases: `sqlalchemy.sql.functions.GenericFunction`

  `identifier` = 'char_length'
  `name` = 'char_length'
  `type`

    alias of `Integer`

class `sqlalchemy.sql.functions.``coalesce`(*args, **kwargs)

  Bases: `sqlalchemy.sql.functions.ReturnTypeFromArgs`

  `identifier` = 'coalesce'
  `name` = 'coalesce'

class `sqlalchemy.sql.functions.``concat`(*args, **kwargs)

  Bases: `sqlalchemy.sql.functions.GenericFunction`

  `identifier` = 'concat'
  `name` = 'concat'
  `type`

    alias of `String`

class `sqlalchemy.sql.functions.``count`(expression=None, **kwargs)

  Bases: `sqlalchemy.sql.functions.GenericFunction`

  The ANSI COUNT aggregate function. With no arguments, emits COUNT *.

  `identifier` = 'count'
  `name` = 'count'
  `type`

    alias of `Integer`

class `sqlalchemy.sql.functions.``current_date`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'current_date'
  `name` = 'current_date'
  `type`

    alias of `Date`

class `sqlalchemy.sql.functions.``current_time`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'current_time'
  `name` = 'current_time'
  `type`

    alias of `Time`

class `sqlalchemy.sql.functions.``current_timestamp`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'current_timestamp'
  `name` = 'current_timestamp'
  `type`

    alias of `DateTime`

class `sqlalchemy.sql.functions.``current_user`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'current_user'
  `name` = 'current_user'
  `type`

    alias of `String`

class `sqlalchemy.sql.functions.``localtime`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'localtime'
  `name` = 'localtime'
  `type`

    alias of `DateTime`

class `sqlalchemy.sql.functions.``localtimestamp`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'localtimestamp'
  `name` = 'localtimestamp'
  `type`

    alias of `DateTime`

class `sqlalchemy.sql.functions.``max`(*args, **kwargs)

  Bases: `sqlalchemy.sql.functions.ReturnTypeFromArgs`

  `identifier` = 'max'
  `name` = 'max'

class `sqlalchemy.sql.functions.``min`(*args, **kwargs)

  Bases: `sqlalchemy.sql.functions.ReturnTypeFromArgs`

  `identifier` = 'min'
  `name` = 'min'

class `sqlalchemy.sql.functions.``next_value`(seq, **kw)

  Bases: `sqlalchemy.sql.functions.GenericFunction`

  Represent the ‘next value’, given a `Sequence` as it’s single argument.

  Compiles into the appropriate function on each backend, or will raise NotImplementedError if used on a backend that does not provide support for sequences.

  `identifier` = 'next_value'
  `name` = 'next_value'
  `type` = Integer()

class `sqlalchemy.sql.functions.``now`(*args, **kwargs)

  Bases: `sqlalchemy.sql.functions.GenericFunction`

  `identifier` = 'now'
  `name` = 'now'
  `type`

    alias of `DateTime`

class `sqlalchemy.sql.functions.``random`(*args, **kwargs)

  Bases: `sqlalchemy.sql.functions.GenericFunction`

  `identifier` = 'random'
  `name` = 'random'

`sqlalchemy.sql.functions.``register_function`(identifier, fn, package='_default')

  Associate a callable with a particular func. name.

  This is normally called by _GenericMeta, but is also available by itself so that a non-Function construct can be associated with the `func` accessor (i.e. CAST, EXTRACT).

class `sqlalchemy.sql.functions.``session_user`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'session_user'
  `name` = 'session_user'
  `type`

    alias of `String`

class `sqlalchemy.sql.functions.``sum`(*args, **kwargs)

  Bases: `sqlalchemy.sql.functions.ReturnTypeFromArgs`

  `identifier` = 'sum'
  `name` = 'sum'

class `sqlalchemy.sql.functions.``sysdate`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'sysdate'
  `name` = 'sysdate'
  `type`

    alias of `DateTime`

class `sqlalchemy.sql.functions.``user`(**kwargs)

  Bases: `sqlalchemy.sql.functions.AnsiFunction`

  `identifier` = 'user'
  `name` = 'user'
  `type`

    alias of `String`