rand()的订单处理大型帖子时遇到麻烦 [英] order by rand() gets trouble for large posts

问题描述

我有这段代码，这段代码很麻烦，要花很多时间才能显示来自DB的RANDOM帖子:

I have this code, this code gets trouble and so much time to be executed to show RANDOM posts from DB:

$totalrows = 10;

$sql = "SELECT 
 posts.Tags as tags, 
 posts.OwnerUserId as postsid, 
 posts.Id as postid, 
 posts.Body as body, 
 posts.Title as title, 
 users.Id as userid, 
 users.DisplayName as usersname  
FROM posts 
JOIN users ON posts.OwnerUserId = users.Id 
WHERE posts.Title != '' order by rand() asc limit " .  $totalrows;

$r = mysql_query($sql) or die(mysql_error());

请告诉我我应该更改些什么以更快地显示随机帖子?

Please tell me what should I change to show random posts more quikly?

问候，丹

推荐答案

rand()非常昂贵.这将有助于:

rand() is very expensive. This will help: http://www.titov.net/2005/09/21/do-not-use-order-by-rand-or-how-to-get-random-rows-from-table/

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