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Showing results for tags 'random'.
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SELECT user_id FROM users WHERE active = :active ORDER BY RAND() LIMIT 1 The above query works. But what if the users table is filled with thousands of users? Will this query break or be very slow? If so, what's the alternative solution to this? -
Hi All, I'm looking to update a mysql column weekly, where by 5 randomly selected rows are given a new random number, from between 1 and the num_rows / 5. This cycle is looped again until all the entries have a new random group for the week. It is to help mix up the players for teams for 5 aside. It needs to be able to accomodate the posibillity of the num_rows not dividing exactly by 5, using ceil perhaps? As an example Name Group a 1 b 2 c 1 d 1 e 1 f 3 g 2 h 1 i 2 j 2 k 2 Then Next week Name Group a 2 b 1 c 2 d 2 e 1 f 2 g 3 h 1 i 2 j 1 k 1 I hope that makes sense. It'll be automated via cron job. I've been really struggling with it, this is as far as I have got. $totalgroupsraw = $num_rows /5; $totalgroups = ceil ($totalgroupsraw); $i = 1; while ($i<$totalgroups) { $pie = mysql_query("UPDATE table SET columnname=5 order by rand() LIMIT 5"); $i++; }; But as you will no doubt be able to see, this doesn't work well at all. I think I am close, but I just can't seem to sort out a good way to do it. Any help much appreciated. Thanks, Matt