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Classe « Query »

Méthode sqlalchemy.orm.Query.distinct

Signature de la méthode distinct

def distinct(self, *expr: '_ColumnExpressionArgument[Any]') -> 'Self' 

Description

help(Query.distinct)

Apply a ``DISTINCT`` to the query and return the newly resulting
``Query``.


.. note::

    The ORM-level :meth:`.distinct` call includes logic that will
    automatically add columns from the ORDER BY of the query to the
    columns clause of the SELECT statement, to satisfy the common need
    of the database backend that ORDER BY columns be part of the SELECT
    list when DISTINCT is used.   These columns *are not* added to the
    list of columns actually fetched by the :class:`_query.Query`,
    however,
    so would not affect results. The columns are passed through when
    using the :attr:`_query.Query.statement` accessor, however.

    .. deprecated:: 2.0  This logic is deprecated and will be removed
       in SQLAlchemy 2.0.     See :ref:`migration_20_query_distinct`
       for a description of this use case in 2.0.

.. seealso::

    :meth:`_sql.Select.distinct` - v2 equivalent method.

:param \*expr: optional column expressions.  When present,
 the PostgreSQL dialect will render a ``DISTINCT ON (<expressions>)``
 construct.

 .. deprecated:: 1.4 Using \*expr in other dialects is deprecated
    and will raise :class:`_exc.CompileError` in a future version.

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