结合2个sqlalchemy查询和排序

Question

I'm using the results of one query to process another and then add that data to the original query object. I'd then like to order the results by that data.

Here's what I have at the moment:

def driver():
    sess = session()
    data = sess.query(DriversConstructors).filter(DriversConstructors.TYPE_ID==1).all()
    for driver in data:
        p = sess.query(func.sum(FantasyResults.POINTS)).filter(FantasyResults.DRIVER_CONSTRUCTOR_ID==driver._ID).scalar()
        driver.points = int(p)
    sess.close()
    return data

so basically the results need to be ordered by points.

I'm pretty confident there is a much better way of doing this so any help would be appreciated.

Answer 1

If I have understood correctly, what you need is a JOIN and some grouping in order to move the operation to the database system:

def driver(type_id=1):
    sess = session()
    try:
        return sess.query(DriversConstructors).\
            outerjoin(FantasyResults,
                      FantasyResults.DRIVER_CONSTRUCTOR_ID == DriversConstructors._ID). \
            filter(DriversConstructors.TYPE_ID == type_id). \
            group_by(DriversConstructors._ID). \
            order_by(func.sum(FantasyResults.POINTS)). \
            all()

    finally:
        sess.close()