Classe « Query »

Méthode sqlalchemy.orm.Query.union

Signature de la méthode union

def union(self, *q) 

Description

union.__doc__

Produce a UNION of this Query against one or more queries.

        e.g.::

            q1 = sess.query(SomeClass).filter(SomeClass.foo=='bar')
            q2 = sess.query(SomeClass).filter(SomeClass.bar=='foo')

            q3 = q1.union(q2)

        The method accepts multiple Query objects so as to control
        the level of nesting.  A series of ``union()`` calls such as::

            x.union(y).union(z).all()

        will nest on each ``union()``, and produces::

            SELECT * FROM (SELECT * FROM (SELECT * FROM X UNION
                            SELECT * FROM y) UNION SELECT * FROM Z)

        Whereas::

            x.union(y, z).all()

        produces::

            SELECT * FROM (SELECT * FROM X UNION SELECT * FROM y UNION
                            SELECT * FROM Z)

        Note that many database backends do not allow ORDER BY to
        be rendered on a query called within UNION, EXCEPT, etc.
        To disable all ORDER BY clauses including those configured
        on mappers, issue ``query.order_by(None)`` - the resulting
        :class:`_query.Query` object will not render ORDER BY within
        its SELECT statement.