Using alias() for 'select as' in SQLAlchem

问题:

Let's say I have a table 'shares' with the following columns:

company    price    quantity
Microsoft  100      10
Google     99       5
Google     99       20
Google     101      15

I'd like to run the equivalent of a SQL statement like this:

select price, sum(quantity) as num from shares where company='Google' group by price;

The closest I've come is:

result = dbsession.query(Shares.price, func.sum(Shares.quantity)).filter(Shares.company== 'Google').group_by(Shares.price).all()

I'm having trouble with setting up the 'sum(quantity) as num' in sqlalchemy. It appears I need to use alias() but I can't figure out how by looking at the documentation. I'd be grateful if someone could show me how to do it.

Many thanks!

回答1:

You actually want the label method.

result = dbsession.query(Shares.price, \
                            func.sum(Shares.quantity).label("Total sold")) \
                            .filter(Shares.company== 'Google') \
                            .group_by(Shares.price).all()