前言:
1,常碰到的排名需求:不并列排名(1,2,3,4,5,6),并列排名(不占位)(1,2,3,3,4,5),并列排名(占位)(1,2,3,3,5,6),查询指定用户排名
2,@rank := @rank + 1 :其中 := 是赋值的作用,这句话的意思是先执行@rank + 1,然后把值赋给@rank
3,(SELECT @rank := 0) r :这句话的意思是设置rank字段的初始值为0
正文:
不并列排名:
方法1:先排序,再对结果进行编号
SELECT t.*, @rank := @rank + 1 AS rank FROM (SELECT @rank := 0) r, (SELECT * FROM testsort ORDER BY score DESC) t;
方法2:先查询结果,再排序编号
SELECT t.*, @rank := @rank + 1 AS rank FROM (SELECT @rank := 0) r, testsort t ORDER BY t.score DESC;
结果是一样的
并列排名(不占位):
-- 记录下当次的分数。下次判断如果分数一致,排名不变。如果不一致,更新分数,排名+1 SELECT obj.uid, obj.score, CASE WHEN @last_score = obj.score THEN @last_rank WHEN @last_score := obj.score THEN @last_rank := @last_rank + 1 END AS rank FROM ( SELECT uid, score FROM testsort ORDER BY score DESC ) obj, ( SELECT @last_rank := 0 , @last_score := NULL) r
并列排名(占位):
-- 记录下当次的分数和排名,@rank每次都+1。下次判断如果分数一致,排名不变。如果不一致,更新分数,排名用@rank SELECT obj.uid, obj.score, @rank := @rank + 1, @last_rank := CASE WHEN @last_score = obj.score THEN @last_rank WHEN @last_score := obj.score THEN @rank END AS rank FROM ( SELECT uid, score FROM testsort ORDER BY score DESC ) obj, ( SELECT @last_rank := 0 , @last_score := NULL, @last_rank := 0) r
查询指定用户排名:
SELECT b.* FROM ( SELECT t.*, @rank := @rank + 1 AS rank FROM (SELECT @rank := 0) r, (SELECT * FROM testsort ORDER BY score DESC) t; ) AS b WHERE b.uid = x;
參考博客:
MYSQL实现排名及查询指定用户排名功能(并列排名功能)实例代码_Mysql_脚本之家
https://www.jb51.net/article/148757.htm
Mysql实现排名函数的三种方法 - mingqing6364 - CSDN博客
https://blog.csdn.net/mingqing6364/article/details/82621840
MySql并列排名 - whyalwaysmea - CSDN博客
https://blog.csdn.net/u013435893/article/details/80350269