Use raw SQL in an ORM query

Question

Is it possible to make edits or override the ORM\'s generated SQL with your own raw SQL? Or is the ORM expected to be flexible enough to build pretty much any query I could

Answer 1

You can build it by aliasing the Model first and then using that alias as the second table to an outer join. The following assumes that you already have a session that is bound to a working engine:

from sqlalchemy.orm import aliased
from sqlalchemy import and_


allocation_status2 = aliased(AllocationStatus)
session.query(AllocationStatus).\
    outerjoin(allocation_status2,
              and_(AllocationStatus.allocation_id == allocation_status2.allocation_id,
                   AllocationStatus.id < allocation_status2.id)).\
    filter(allocation_status2.id.is_(None)).all()

I hope this helps.