Sqlalchemy in_ subquery

Question

I am trying to implement a select with a nested select clause, to find parents without any children. My tables (radically simplified) are as follows:

class Pers         


        

Answer 1

Join worked for me. Thank you. In my case I was trying to find all ordered objects (Topics) which belong to a particular customer. I have 3 tables Customer, Order, Topics

stmt = db.session.query(Topics).outerjoin(Order).\
    filter(Order.cust_id == id)

topics = stmt.all()