求化

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')

查句有有一的法呢
或者用存程？
[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

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