使用嵌套select子式 解决mysql不能叠加使用如max(sum())的问题
作者: default|标签:select 解决 子式|2018-5-16 16:52

网上也有解决方案 有的有瑕疵 有的较复杂(mysql没有分析函数,可以使用变量实现) s

elect sumScoreValue,studentid,studentName from sc_studentb, ( select sum (scoreValue) as sumScoreValue,studentid from sc_score group by studentid order by sumSc

网上也有解决方案 有的有瑕疵 有的较复杂(mysql没有分析函数,可以使用变量实现)

select sumScoreValue,studentid,studentName from sc_student b,  
(select sum(scoreValue) as sumScoreValue, studentid   
from sc_score group by studentid       
order by sumScoreValue desc limit 1) as a  
where a.studentid=b.studentNo  
//这样做 只能查询第一名只有一个的情况 很巧妙
mysql> select studentid,scoreValue from sc_score;  
+-----------+------------+  
| studentid | scoreValue |  
+-----------+------------+  
|         1 |         80 |  
|         1 |         85 |  
|         1 |         90 |  
|         2 |         75 |  
|         2 |         80 |  
|         2 |         84 |  
|         3 |         85 |  
|         3 |         85 |  
|         3 |         85 |  
+-----------+------------+  
9 rows in set (0.00 sec)  
  
mysql> SELECT studentNo,studentName FROM sc_student;  
+-----------+-------------+  
| studentNo | studentName |  
+-----------+-------------+  
|         1 | aa          |  
|         2 | bb          |  
|         3 | cc          |  
+-----------+-------------+  
3 rows in set (0.00 sec)  
  
  
mysql> SELECT a.studentid,  
    ->        b.studentName,  
    ->        a.sumScoreValue  
    ->   FROM (SELECT tmp.studentid,  
    ->                tmp.sumScoreValue,  
    ->                IF(@groupid = tmp.sumScoreValue,@rank := 1,@rank := @rank + 1) AS rank,  
    ->                @groupid := tmp.sumScoreValue  
    ->           FROM (SELECT studentid,  
    ->                        SUM(scoreValue) AS sumScoreValue  
    ->                   FROM sc_score  
    ->                  GROUP BY studentid  
    ->                  ORDER BY scoreValue DESC) tmp,  
    ->                (SELECT @rank := 0,@groupid := '') m) a,  
    ->        sc_student b  
    ->  WHERE a.studentid = b.studentNo  
    ->    AND a.rank = 1;  
+-----------+-------------+---------------+  
| studentid | studentName | sumScoreValue |  
+-----------+-------------+---------------+  
|         3 | cc          |           255 |  
|         1 | aa          |           255 |  
+-----------+-------------+---------------+  
2 rows in set (0.00 sec)

这是使用变量做的

自己重新做了

select s.id,s.stuid,stu.stuname, sumscore
from score s left join student stu on s.stuid = stu.stuid left join (select s.id,s.stuid,stu.stuname,sum(s.score) as sumscore
from score s left join student stu on s.stuid = stu.stuid where s.gradeid=4 and s.classid=1 and s.season=1 group by s.stuid)  as t1 on t1.id=s.id  where s.gradeid=4 and s.classid=1 and s.season=1  and sumscore in(select max(sumscore) from (select s.id,s.stuid,stu.stuname,sum(s.score) as sumscore
from score s left join student stu on s.stuid = stu.stuid where s.gradeid=4 and s.classid=1 and s.season=1 group by s.stuid) as t2)
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  • IF(@groupid=tmp.sumScoreValue, @rank:=@rank,@rank:=@rank+1) as rank,
    时间: 2018-03-15
  • 使用变量实现,有问题哦
    时间: 2018-03-15
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