mysql - How to Find Count After Join in SQLAlchemy -

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i join multiple tables with:

session.query(r, rr, rrr).join(r).join(rr).all()

i tried:

session.query(func.count(r, rr, rrr)).join(r).join(rr)

however, not appear correct approach determining count tables.

i 

len(session.query(r, rr, rrr).join(r).join(rr).all())

but ideally, won't have counts in memory.

if after count(*), below should work:

q = (session      .query(func.count().label("cnt"))      .select_from(r)      .join(rr)      .join(rrr)      ) r = q.scalar()

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