Hi. In a mysql query, it is recommended that "GROUP BY" fields be indexed? Using EXPLAIN on one of my queries, I noticed no change between having indexed by GROUP BY field and not indexing it. Any thoughts would be appreciated. In this example, should `history_field` be indexed...? SELECT MAX(`timestamp`) AS `max_ts` FROM `history` WHERE `req_id` = 17 AND `history_record_id` = 35 GROUP BY `history_field` Thanks, ~Philip -- PHP Database Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php