求優化,该如何解决

2012-09-18

求優化SQL codeselect name from STUDENT where id in (select studentid from EXAM where score in(SELEC

求優化

SQL code

select name from STUDENT where id in (select studentid from EXAM where score in(SELECT score FROM EXAM WHERE lessonid='10004' group by score having score <=(select avg(score) from EXAM where Lessonid ='10004') )and lessonid ='10004')

這個查詢語句有沒有簡單一點的寫法呢
或者用存儲過程？

[解决办法]
你的语句怎么要4层查询啊？太复杂了吧？不就是找出10004这门课低于平均分的学生吗？试试下面的，没数据不要测

SQL code

SELECT  nameFROM    STUDENTWHERE   id IN ( SELECT  studentid                FROM    EXAM                WHERE   lessonid = '10004'                        AND score <= ( SELECT   AVG(score)                                       FROM     EXAM                                       WHERE    Lessonid = '10004'                                     ) )

热点排行

SQL Server

求優化,该如何解决