Method union

lib/sqlalchemy/orm/query.py:2128–2173

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

(self, *q: Query[Any])

        return self._from_selectable(expr_fn(*(list_of_queries)).subquery())

    def union(self, *q: Query[Any]) -> Self:
        """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:

        .. sourcecode:: sql

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

        Whereas::

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

        produces:

        .. sourcecode:: sql

            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.

        .. seealso::

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

        """
        return self._set_op(expression.union, *q)

    def union_all(self, *q: Query[Any]) -> Self:
        """Produce a UNION ALL of this Query against one or more queries.