mysql 排序并增加序号，分数相同并列

1，排序，根据总分 增加序号

  表结构：

sql：

SET @row=0;
SELECT b.*, @row:=@row+1 rownum FROM (
select *,SUM(a.achievement) as achievementAll from cp_cj as a
where 1=1 GROUP BY a.studentNum order by SUM(a.achievement) DESC limit 0,30
) as b

结果：

2，排序，根据总分 增加序号，并且按照总分相同的并列

sql：

select c.* ,ifnull((
select count(*) from
(
select *,SUM(a.achievement) as achievementAll from cp_cj as a
where 1=1 GROUP BY a.studentNum order by SUM(a.achievement) DESC 
) as b
where c.achievementAll < b.achievementAll

),0)+1 as rownum from
(
select *,SUM(a.achievement) as achievementAll from cp_cj as a
where 1=1 GROUP BY a.studentNum order by SUM(a.achievement) DESC limit 0,30
) as c

结果：