On Thu, Jul 23, 2009 at 3:24 PM, Michael Bayer<mike...@zzzcomputing.com> wrote:
> im assuming you're using MySQL since the GROUP BY below doesn't > accommodate every column in the subquery (would be rejected by most DBs). Corrected. It was Sqlite, but good catch. > youll want to query each column individually that is part of what you are > grouping by. i think you also need to use func.max() here and not > func.min(). Yes, dumbpants on me there! the join of the subquery to parent table is then probably > just on hop_id. no "correlation" of subquery is needed either since you > are intersecting two complete sets together (all routes intersected with > all "max hop id" routes grouped by x, y, z). > How do I implement this join? If I do this: sq = session.query(Route.ts,Route.startpoint,Route.target,func.max(Route.hop_id).label('max_hop')) sq = sq.group_by(Route.ts,Route.startpoint,Route.target).subquery() then: q = session.Query(Route,*sq.c).join(???) What would that join be on? Hop_id isn't in the subquery. I don't mean to be dense, but I'm not quite getting your response. Perhaps I don't understand what correlated subqueries in SqlA are. Is there is a reference that explains where they're used? --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---