[英]How can I create a mysql_query that pulls items ranked using a Bayesian average?
[英]Query to get grouped items ranked?
我有一个针对各种用户的命中表:
HITS:
id | userid
1 | 1
2 | 1
3 | 2
4 | 1
5 | 2
6 | 2
我想以最快的方式获得按ID排序的这些项目的列表。 所以这:
HITS RANKED:
id | userid | ranks
1 | 1 | 1
2 | 1 | 2
3 | 2 | 1
4 | 1 | 3
5 | 2 | 2
6 | 2 | 3
我要避免将两个表相互连接,因为当表变大时,这将永远花费。 还有其他建议吗?
SELECT ID,
UserID,
Ranks
FROM
(
SELECT id,
userid,
@group:=CASE WHEN @temp <> userid THEN 1 ELSE @group+1 END AS ranks,
@temp:=userid AS clset
FROM (SELECT @group:= 0) s,
(SELECT @temp:= 0) c,
(SELECT * FROM hits ORDER BY userid, id) t
) x
ORDER BY ID
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