题解 | #查找入职员工时间排名倒数第三的员工所有信息#

先求和，然后排名，最后取出排名为1的

SELECT a.name,b.gsum
FROM user a,(SELECT user_id,gsum,DENSE_RANK()OVER(ORDER BY gsum DESC) AS rank
             FROM(SELECT user_id,SUM(grade_num) AS gsum
                  FROM grade_info
                  GROUP BY user_id)) b
WHERE a.id = b.user_id
GROUP BY user_id
HAVING  b.rank = 1;