I really hate to throw this into the mix, but in my experience it has to do with a combination of issues. The DB used and the configuration of the DB can make a big difference. When I used Oracle, the DBA used to tell me that he could configure it to either use the indexes that we wrote, or he could configure it so that it would dissect every query and figure out on it's own which indexes to use.
In my opinion (fwiw) the best thing you can do is take your query and run it through your DB and see how it handles each one. Also keep an eye on index usage vs cache usage. Query optimization is a fun task that can make you lose your hair. Good luck, Brian Goralczyk Phone 574-643-1144 Email [email protected] _______________________________________________________________________________ UNSUBSCRIBE or access ARSlist Archives at www.arslist.org attend wwrug11 www.wwrug.com ARSList: "Where the Answers Are"
