Hi i recommend always use indexes when programming. developers tend not to.. and when the databases grows it's difficult to modify or make them modify the code.
El mié, 09-12-2009 a las 14:22 -0300, Julio Araya escribió: > On Wed, Dec 9, 2009 at 12:52 PM, Philip Thompson <philthath...@gmail.com> > wrote: > > 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` > > always depends on how many records you have, if you have 100-1000 > records is very diferent to 100000-500000 > > > > > > Thanks, > > ~Philip > > -- > > PHP Database Mailing List (http://www.php.net/) > > To unsubscribe, visit: http://www.php.net/unsub.php > > > > > > > > -- > Julio Araya C. Linux User > #386141 > Memorista de Ingeniería Civil Informática Ubuntu User #14778 > Universidd Técnica Federico Santa María Valparaíso - Chile > -- PHP Database Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
