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Classe « Select »

Méthode sqlalchemy.Select.outerjoin

Signature de la méthode outerjoin

def outerjoin(self, target: '_JoinTargetArgument', onclause: 'Optional[_OnClauseArgument]' = None, *, full: 'bool' = False) -> 'Self' 

Description

help(Select.outerjoin)

Create a left outer join.

Parameters are the same as that of :meth:`_expression.Select.join`.

.. versionchanged:: 1.4 :meth:`_expression.Select.outerjoin` now
   creates a :class:`_sql.Join` object between a
   :class:`_sql.FromClause` source that is within the FROM clause of
   the existing SELECT, and a given target :class:`_sql.FromClause`,
   and then adds this :class:`_sql.Join` to the FROM clause of the
   newly generated SELECT statement.    This is completely reworked
   from the behavior in 1.3, which would instead create a subquery of
   the entire
   :class:`_expression.Select` and then join that subquery to the
   target.

   This is a **backwards incompatible change** as the previous behavior
   was mostly useless, producing an unnamed subquery rejected by
   most databases in any case.   The new behavior is modeled after
   that of the very successful :meth:`_orm.Query.join` method in the
   ORM, in order to support the functionality of :class:`_orm.Query`
   being available by using a :class:`_sql.Select` object with an
   :class:`_orm.Session`.

   See the notes for this change at :ref:`change_select_join`.

.. seealso::

    :ref:`tutorial_select_join` - in the :doc:`/tutorial/index`

    :ref:`orm_queryguide_joins` - in the :ref:`queryguide_toplevel`

    :meth:`_expression.Select.join`

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