On Fri, April 8, 2005 7:41 am, kyriacos sakkas said: > first I would suggest you get the largest value from the auto increment > field (maybe use last_insert_id()). Then use rand(1,$cno_max) three > times to get three random cno numbers, then "select ... from ... where > cno=$val1 or cno=$val2 or cno=$val3" should return the three values. > rand() can also be directly in the sql statement. > Also manual suggests using mt_rand instead of rand for better performance. Reasons NOT to do this: If you ever delete a record, then $val2 might not *BE* there. To get the max(id) requires an extra query. MySQL does *NOT* promise the numbers will be 1, 2, 3, 4, ... Sure, they happen to be that *NOW* and it's unlikely to change, but it's *NOT* a documented feature. What if $val1 and $val2 both happen to come out as "42" one day? Then you're not going to get 3 different records. ORDER BY rand() will always return 3 different records. It's unlikely that PHP's mt_rand() will be enough faster to justify using it when a single SQL statement is so much more clear than 5 lines of PHP. -- Like Music? http://l-i-e.com/artists.htm -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
