MySQL实现排名并查询指定信息排名功能,并列排名功能
at 5年前 ca 记录笔记 pv 1666 by authorhu
思路:可以先排序,再对结果进行编号;也可以先查询结果,再排序编号。
说明:
@rownum := @rownum + 1 中 := 是赋值的作用,这句话的意思是先执行@rownum + 1,然后把值赋给@rownum;
(SELECT @rownum := 0) r 这句话的意思是设置rownum字段的初始值为0,即编号从1开始。
实现排名:
方法一:
SELECT t.*, @rownum := @rownum + 1 AS rownum FROM (SELECT @rownum := 0) r, (SELECT * FROM testsort ORDER BY score DESC) AS t;
方法二:
SELECT t.*, @rownum := @rownum + 1 AS rownum FROM (SELECT @rownum := 0) r, testsort AS t ORDER BY t.score DESC;
查看指定用户排名:
方法一:
SELECT b.* FROM ( SELECT t.*, @rownum := @rownum + 1 AS rownum FROM (SELECT @rownum := 0) r, (SELECT * FROM testsort ORDER BY score DESC) AS t ) AS b WHERE b.uid = 222;
方法二:
SELECT b.* from ( SELECT t.*, @rownum := @rownum + 1 AS rownum FROM (SELECT @rownum := 0) r, testsort AS t ORDER BY t.score DESC ) as b where b.uid = 222;
////////////////////////////////////////实例/////////////////////////////////
<?php $csql=$empire->fetch1("SELECT b.* FROM( SELECT t.*, @rownum := @rownum + 1 AS rownum FROM (SELECT @rownum := 0) r, (SELECT * FROM ecms_games where leixing = 2 ORDER BY onclick DESC) AS t ) AS b WHERE b.id = 11;"); if($csql) echo $csql[rownum]; ?>
实现并列排名(相同分数排名相同):
SELECT
obj.uid,
obj.score,
CASE
WHEN @rowtotal = obj.score THEN
@rownum
WHEN @rowtotal := obj.score THEN
@rownum :=@rownum + 1
WHEN @rowtotal = 0 THEN
@rownum :=@rownum + 1
END AS rownum
FROM
(
SELECT
uid,
score
FROM
testsort
ORDER BY
score DESC
) AS obj,
(SELECT @rownum := 0 ,@rowtotal := NULL) r
查询指定用户并列排名:
SELECT total.* FROM
(SELECT
obj.uid,
obj.score,
CASE
WHEN @rowtotal = obj.score THEN
@rownum
WHEN @rowtotal := obj.score THEN
@rownum :=@rownum + 1
WHEN @rowtotal = 0 THEN
@rownum :=@rownum + 1
END AS rownum
FROM
(
SELECT
uid,
score
FROM
testsort
ORDER BY
score DESC
) AS obj,
(SELECT @rownum := 0 ,@rowtotal := NULL) r) AS total WHERE total.uid = 222;
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本文仅代表作者观点,未经许可,不得转载。