SQLAlchemy and empty IN clause

Question

I found out that SQLAlchemy translates

db.query(...).filter(A.id.in_(ids))

into

SELECT ...
FROM a
WHERE a.id != a.id
         


        

Answer 1

I'm using:

if len(ids) > 0:
    db.query(...).where(A.id.in_(ids))
else:
    db.query(...).where(False)

I tried a .limit(0) instead of the .where(false) without success. There is some behind-the-scenes difference in the empty querysets that broke other stuff down the pipeline. This workaround, while could be faster, at least avoids your mentioned warning.