MySQL实现排名并查询指定用户排名功能，并列排名功能
MySQL实现排名并查询指定用户排名功能，并列排名功能
表结构： CREATE TABLE test.testsort ( id int(11) NOT NULL AUTO_INCREMENT, uid int(11) DEFAULT 0 COMMENT '用户id', score decimal(10, 2) DEFAULT 0.00 COMMENT '分数', PRIMARY KEY (id) ) ENGINE = INNODB AUTO_INCREMENT = 1 CHARACTER SET utf8 COLLATE utf8_general_ci COMMENT = '测试排序' ROW_FORMAT = DYNAMIC; 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; 结果：
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; 结果：
SRE实战 互联网时代守护先锋，助力企业售后服务体系运筹帷幄！一键直达领取阿里云限量特价优惠。 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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