SQLAlchemy - subquery in a WHERE clause

Question

I\'ve just recently started using SQLAlchemy and am still having trouble wrapping my head around some of the concepts.

Boiled down to the essential elements, I have

Answer 1

the previous answer works, but also the exact sql you asked for is written much as the actual statement:

print s.query(User, Posts).\
    outerjoin(Posts.user).\
    filter(Posts.post_time==\
        s.query(
            func.max(Posts.post_time)
        ).
        filter(Posts.user_id==User.user_id).
        correlate(User).
        as_scalar()
    )

I guess the "concept" that isn't necessarily apparent is that as_scalar() is currently needed to establish a subquery as a "scalar" (it should probably assume that from the context against ==).

Edit: Confirmed, that's buggy behavior, completed ticket #2190. In the current tip or release 0.7.2, the as_scalar() is called automatically and the above query can be:

print s.query(User, Posts).\
    outerjoin(Posts.user).\
    filter(Posts.post_time==\
        s.query(
            func.max(Posts.post_time)
        ).
        filter(Posts.user_id==User.user_id).
        correlate(User)
    )