count rows on relation?

[Former user]

hello can you implement a feature to more easily count rows on relation - for example i have relation one-to-many (a to b) named myb and i want to count all 'b' belonging to 'a'. to get count i have to do query(b).filter_by(b.fromFK=a.PK).count() it will be cool if there can be easer way to do that - may be something like - a.myb.count() which makes SELECT COUNT(*) on B. thx

[Mike Bayer]

we have query(b).with_parent(a).count().