Is explicit CROSS JOIN possible with SQLAlchemy?

Question

Is it possible to generate an explicit CROSS JOIN query with SQLAlchemy as the following example:

SELECT * 
FROM foo 
CROSS JOIN bar

And if

Answer 1

SQLAlchemy doesn't have explicit way to specify CROSS JOIN. IMHO all major relation databases do CROSS JOIN when you has tables in FROM clause, but no join criteria between them.

I would suggest to use SQL Expression API and not SQLAlchemy ORM API for tasks like that - so you'll get resulting records and otherwise SQLAlchemy ORM API will try to do object mapping. For your example I assume that Foo and Bar are mapped classes:

connection.execute(select[Foo.__table__,Bar.__table__])

Please see example from the SQLAlchemy manual describing how to make query generate Cartesian product; each row from the users table is produced against each row from the addresses table:

>>> for row in conn.execute(select([users, addresses])):
...     print row  
SELECT users.id, users.name, users.fullname, addresses.id, addresses.user_id, addresses.email_address
FROM users, addresses
()

Answer 2

You can make cartesian product using inner join, applying condition which is always true. E.g. for SQLAlchemy ORM:

from sqlalchemy.sql.expression import literal

session.query(Foo, Bar).join(Bar, literal(True)).all()

There're only join and outerjoin functions in SQLAlchemy for now (v0.9).