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gh-79097: Add support for aggregate window functions in sqlite3 (GH-20903)

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Erlend Egeberg Aasland 2022-04-12 02:55:59 +02:00 • committed by GitHub
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Doc/library/sqlite3.rst
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@ -473,6 +473,35 @@ Connection Objects
.. literalinclude:: ../includes/sqlite3/mysumaggr.py
.. method:: create_window_function(name, num_params, aggregate_class, /)
Creates user-defined aggregate window function *name*.
*aggregate_class* must implement the following methods:
* ``step``: adds a row to the current window
* ``value``: returns the current value of the aggregate
* ``inverse``: removes a row from the current window
* ``finalize``: returns the final value of the aggregate
``step`` and ``value`` accept *num_params* number of parameters,
unless *num_params* is ``-1``, in which case they may take any number of
arguments. ``finalize`` and ``value`` can return any of the types
supported by SQLite:
:class:`bytes`, :class:`str`, :class:`int`, :class:`float`, and
:const:`None`. Call :meth:`create_window_function` with
*aggregate_class* set to :const:`None` to clear window function *name*.
Aggregate window functions are supported by SQLite 3.25.0 and higher.
:exc:`NotSupportedError` will be raised if used with older versions.
.. versionadded:: 3.11
Example:
.. literalinclude:: ../includes/sqlite3/sumintwindow.py
.. method:: create_collation(name, callable)
Creates a collation with the specified *name* and *callable*. The callable will