[Jeffrey W. Baker - Thu at 06:56:59PM -0700] > > explain select c.id from c join b on c_id=c.id group by c.id order by c.id > > desc limit 5; > > Where's b in this join clause?
"join b on c_id=c.id" It just a funny way of writing: select c.id from c,b where c_id=c.id group by c.id order by c.id desc limit 5; > It looks like a cartesian product to me. No. The query will return exactly the same as the simplest query: select c.id from c order by c.id desc limit 5; As said, this is a gross oversimplification of the production envorinment. In the production environment, I really need to use both join, group and limit. I tested a bit with subqueries, it was not a good solution (selecting really a lot of rows and aggregates from many of the tables). The next idea is to hack it up by manually finding out where the "limit" will cut, and place a restriction in the where-part of the query. -- Notice of Confidentiality: This information may be confidential, and blah-blah-blah - so please keep your eyes closed. Please delete and destroy this email. Failure to comply will cause my lawyer to yawn. ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings