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

use subquery, if ids is empty, will (never executed).

example:

subquery = db.query(SomeTable.id).filter(...).subquery()

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

into:

SELECT ...
FROM a
WHERE a.id IN (SELECT ...)