mysql 实现row_number() over(partition by ) 分组排序功能

创建表：

插入数据：

生成行号：

生成row_number效果1：

生成row_number效果2：

注意点：“

SELECT IF(@UID = T.ID AND @CID = T.PID,

          @RANK := @RANK + 1,

          @RANK := 1) AS RANK2,

”需要命名别名

附：代码

DESC USERS; 

 

SELECT * FROM USERS;

-- 给USERS里的数据设置行号, RN是行号

SELECT @ROWNUM := @ROWNUM + 1 AS RN, T.

  FROM (SELECT @ROWNUM := 0) R, USERS T

SELECT IF(@UID = T.ID AND @CID = T.PID,

          @RANK := @RANK + 1,

          @RANK := 1) AS RANK2,

       T.,

       @UID := T.ID,

       @CID := T.PID

  FROM (SELECT @UID := NULL, @CID := NULL, @RANK := 0) R,

       (SELECT   PID, NAME, ID

          FROM USERS

         ORDER BY  PID, NAME, ID) T; 

 

SELECT IF(@UID = T.PID,

          @RANK := @RANK + 1,

          @RANK := 1) AS RANK2,

       T.*,

       @UID := T.ID,

       @CID := T.PID

  FROM (SELECT @UID := NULL, @CID := NULL, @RANK := 0) R,

       (SELECT   PID, NAME, ID

          FROM USERS

         ORDER BY  PID, NAME, ID) T; 

 

 

可以参考的其他类似处理方式：

select *,@rank:=case when @current_id<>pid then 1 else @rank+1 end as rank2,

 @current_id:=id from users order by pid,name desc;

这段不是，记录：

 

SELECT 

ID,SUBSTRING_INDEX(GROUP_CONCAT(PID ORDER BY NAME DESC),',',1) PID 

FROM 

(

    SELECT

  ID,PID,NAME 

    FROM 

    USERS

    ORDER BY PID ASC ,NAME DESC

)B 

    GROUP BY ID

;