What about in MySQL:
SELECT personID from persons ORDER BY RAND(NOW()) LIMIT 1
If the table is large, then the following might be better:
LOCK TABLES foo READ; SELECT FLOOR(RAND() * COUNT(*)) AS rand_row FROM foo; SELECT * FROM foo LIMIT $rand_row, 1; UNLOCK TABLES;
There's a whole discussion on it in the MySQL documentation web site:
http://dev.mysql.com/doc/mysql/en/SELECT.html
On 15 Oct 2004, at 07:41, -{ Rene Brehmer }- wrote:
I made this code to pick a random record from a changeable number of records in a given table.
I'm just curious if any of the more awake coders out there can see a way to optimize this for better performance, since there's several other DB queries on the same page.
$records = mysql_query("SELECT COUNT(*) AS count FROM persons") or die('Unable to get record count<br>'.mysql_error());
$totalcount = mysql_result($records,0) - 1;
$rndrecord = rand(0,$totalcount);
$personquery = mysql_query("SELECT personID FROM persons LIMIT $rndrecord,1") or die('Unable to get random record<br>'.mysql_error());
$personID = mysql_result($personquery,0);
--
Rene Brehmer
aka Metalbunny
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