The Python functions for finding users with failed orders

why_learn_sql.py

from sqlalchemy.orm import Session

...

class User(Base):
    ...

class Order(Base):
    ...

    
def get_users_with_failed_orders_python(session: Session) -> set[User]:
    """Get all users with failed orders using a naive Python implementation."""
    failed_orders = (
        session
        .query(Order)
        .prefix_with('SQL_NO_CACHE')
        .filter(Order.payment_status == False)
        .all()
    )

    users = set()

    for order in failed_orders:
        user = (
            session
            .query(User)
            .prefix_with('SQL_NO_CACHE')
            .filter(User.id == order.user_id)
            .one_or_none()
        )
        users.add(user)

    return users


def get_users_with_failed_orders_sql(session: Session) -> set[User]:
    """Get all users with failed orders using a SQL implementation."""
    return set(
        session
        .query(User)
        .prefix_with('SQL_NO_CACHE')
        .distinct()
        .join(Order)
        .filter(Order.payment_status == False)
        .all()
    )