让MySQL显示每个用户的评分，然后使用评分对结果进行排序？

Question

问：我如何让MySQL也显示每个用户的评分，然后使用评分，desc对结果进行排序？

这全部用于游戏阶梯。 weblGames有每个报道的比赛结果，并有关于谁赢/输的信息以及赢家/输家评分变得如何（赢家_elo & loser_elo）。

下面是表的部分截图：http://www.ubuntu-pics.de/bild/21059/screenshot_87_RTDZBb.png

仅使用此表来对当前MySQL的代码显示（感谢这个地方）每一个球员的名字和游戏的数量，他内最近x天出场， 。

我想保留这些信息，而且还能够输出每一个玩家当前的Elo点（这等于winner_elo 或 loser_elo他最近玩过的游戏。）

这里是代码我现在有，并且显示在X天内每一个球员和他/她的最近玩的游戏数量：

SELECT userid, count(*) as cnt 
FROM 
(
SELECT winner as userid 
from webl_games g 
where (g.reported_on > now() - interval 4 day 
UNION ALL 
SELECT loser as userid 
from webl_games g 
where g.reported_on > now() - interval 4 day 
) t 
GROUP BY userid 
HAVING COUNT(*) >= 3 

Answer 1

SELECT userid, COUNT(*) as cnt, 
     (
     SELECT CASE t.userid WHEN winner THEN winner_elo ELSE loser_elo END 
     FROM webl_games l 
     WHERE t.userid IN (winner, loser) 
     ORDER BY 
       reported_on DESC 
     LIMIT 1 
     ) AS last_elo 
FROM (
     SELECT winner as userid 
     FROM webl_games g 
     WHERE (g.reported_on > now() - interval 4 day 
     UNION ALL 
     SELECT loser as userid 
     FROM webl_games g 
     WHERE g.reported_on > now() - interval 4 day 
     ) t 
GROUP BY 
     userid 

的子查询在这里可以是无效率的。

如果是，你的表中有一个PRIMARY KEY，把它改写为这样的：

SELECT userid, cnt, 
     (
     SELECT q2.userid WHEN winner THEN winner_elo ELSE loser_elo END 
     FROM webl_games l 
     WHERE l.id IN (lwin, llose) 
     ORDER BY 
       reported_on DESC 
     LIMIT 1 
     ) 
FROM (  
     SELECT userid, COUNT(*) as cnt, 
       (
       SELECT id 
       FROM webl_games l 
       WHERE t.userid = winner 
       ORDER BY 
         reported_on DESC 
       LIMIT 1 
       ) AS lwin, 
       (
       SELECT id 
       FROM webl_games l 
       WHERE t.userid = loser 
       ORDER BY 
         reported_on DESC 
       LIMIT 1 
       ) AS llose 
     FROM (
       SELECT winner as userid 
       FROM webl_games g 
       WHERE (g.reported_on > now() - interval 4 day 
       UNION ALL 
       SELECT loser as userid 
       FROM webl_games g 
       WHERE g.reported_on > now() - interval 4 day 
       ) t 
     GROUP BY 
       userid 
     ) q2