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.. _functions_toplevel:
.. _generic_functions:
=========================
SQL and Generic Functions
=========================
.. currentmodule:: sqlalchemy.sql.functions
SQL functions are invoked by using the :data:`_sql.func` namespace.
See the tutorial at :ref:`tutorial_functions` for background on how to
use the :data:`_sql.func` object to render SQL functions in statements.
.. seealso::
:ref:`tutorial_functions` - in the :ref:`unified_tutorial`
Function API
------------
The base API for SQL functions, which provides for the :data:`_sql.func`
namespace as well as classes that may be used for extensibility.
.. autoclass:: AnsiFunction
:exclude-members: inherit_cache, __new__
.. autoclass:: Function
.. autoclass:: FunctionElement
:members:
:exclude-members: inherit_cache, __new__
.. autoclass:: GenericFunction
:exclude-members: inherit_cache, __new__
.. autofunction:: register_function
Selected "Known" Functions
--------------------------
These are :class:`.GenericFunction` implementations for a selected set of
common SQL functions that set up the expected return type for each function
automatically. The are invoked in the same way as any other member of the
:data:`_sql.func` namespace::
select(func.count("*")).select_from(some_table)
Note that any name not known to :data:`_sql.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.
.. autoclass:: array_agg
:no-members:
.. autoclass:: char_length
:no-members:
.. autoclass:: coalesce
:no-members:
.. autoclass:: concat
:no-members:
.. autoclass:: count
:no-members:
.. autoclass:: cube
:no-members:
.. autoclass:: cume_dist
:no-members:
.. autoclass:: current_date
:no-members:
.. autoclass:: current_time
:no-members:
.. autoclass:: current_timestamp
:no-members:
.. autoclass:: current_user
:no-members:
.. autoclass:: dense_rank
:no-members:
.. autoclass:: grouping_sets
:no-members:
.. autoclass:: localtime
:no-members:
.. autoclass:: localtimestamp
:no-members:
.. autoclass:: max
:no-members:
.. autoclass:: min
:no-members:
.. autoclass:: mode
:no-members:
.. autoclass:: next_value
:no-members:
.. autoclass:: now
:no-members:
.. autoclass:: percent_rank
:no-members:
.. autoclass:: percentile_cont
:no-members:
.. autoclass:: percentile_disc
:no-members:
.. autoclass:: random
:no-members:
.. autoclass:: rank
:no-members:
.. autoclass:: rollup
:no-members:
.. autoclass:: session_user
:no-members:
.. autoclass:: sum
:no-members:
.. autoclass:: sysdate
:no-members:
.. autoclass:: user
:no-members:
|
