How To/python/

SqlAlchemy - WHERE [NOT] EXISTS

SQL: WHERE NOT EXISTS

User maps users table.
Car maps cars table.

SELECT users.id FROM users WHERE NOT EXISTS (
   SELECT * FROM cars WHERE users.id = cars.user_id
);

result = session.query(User.id).filter(
    ~exists().where(User.id==Car.user_id)
)

SQL: WHERE EXISTS

User maps users table.
Car maps cars table.

SELECT users.id FROM users WHERE NOT EXISTS (
   SELECT * FROM cars WHERE users.id = cars.user_id
);

result = session.query(User.id).filter(
    exists().where(User.id==Car.user_id)
)