sql查询谁能帮我看下哪里错了

sum(b.ascore)
这里的问题..

改成.

select a.studentid, a.studentname, sum(b.ascore)
from students a,scoreitem b, score
where (a.studentid=b.studentid)
and (score.adate>='2008-1-1' and score.adate<='2008-6-30')
and (score.testid=scoreitem.testid) group by a.studentid,a.studentname
order by a.studentid asc

select a.studentid, a.studentname, sum(b.ascore)
from students a,scoreitem b, score c
where a.studentid=b.studentid and c.testid=a.testid
and c.adate>='2008-1-1' and c.adate<='2008-6-30'
order by a.studentid asc

这样才对

select a.studentid, a.studentname, sum(b.ascore)
from students a,scoreitem b, score
where (a.studentid=b.studentid)
and (score.adate>='2008-1-1' and score.adate<='2008-6-30')
and (score.testid=scoreitem.testid) group by a.studentid,a.studentname
order by a.studentid asc