Dennis Bjorklund <db@xxxxxxxxxxxx> writes: > Look like the mysql people found a subquery that postgresql doesn't > handle as good as possible: > http://s.petrunia.net/blog/ > Is there some deeper issue here that I fail to see or is it simply that > it hasn't been implemented but is fairly straigt forward? I don't think it's straightforward: you'd need to do some careful analysis to prove under what conditions such a transformation would be safe. If the answer is "always, it doesn't matter what the correlation condition is" then the actual implementation would probably not be tremendously difficult. If there are restrictions then checking whether the restrictions hold could be interesting ... regards, tom lane - Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
