求教sql难题
有三张表,一张是学生姓名表T1，一张是成绩表T2,另外一张是科目表T3
T1   字段有   StudentID     Name
T2                 StudentID     CourseID     Score
T3                 CourseID       CourseName
现在要求用sql写出每门科目都大于平均分的考生的成绩,也就是按Ｔ２表输出

------解决方案--------------------
select T2.*
from T2,(select CourseID,avg(Score) as avgScore from T2 group by CourseID) as b
where T2.CourseID=b.CourseID and T2.Score> b.avgScore

或

select a.*
from T2 as a
where a.Score> (select avg(Score) from T2 where a.CourseID=CourseID)