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.reyosoft (
  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 reyosoft
       ORDER BY score DESC) AS t;

 

方法二：

SELECT
  t.*,
  @rownum := @rownum + 1 AS rownum
FROM (SELECT
         @rownum := 0) r,
     reyosoft 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 reyosoft
         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,
       reyosoft AS t
  ORDER BY t.score DESC) AS b
WHERE b.uid = 222;

 

 结果：

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 reyosoft
       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 reyosoft
         ORDER BY score DESC) AS obj,
       (SELECT
           @rownum := 0,
           @rowtotal := NULL) r) AS total
WHERE total.uid = 222;