（Help）inner join连接多表查询出现重复数据 如何解决啊？

[ntwqy_2008]

如题。
使用distinct后数据是1条，如果不使用则出现6条,拜膜高手...

[lizhengnan]

什么意思呀,不明白.
你加上distinct不就得了吗

[ntwqy_2008]

[Quote=引用 1 楼 lizhengnan 的回复:]
什么意思呀,不明白.
你加上distinct不就得了吗
[/Quote]
我使用的asp.net2.0分页控件，如果使用了distinct数据显示在gv中是1条，但是地下的总记录数显示是6，
而且还有一个问题。如下：

select  distinct Count(pj.ProjectID) from OLTR_ExamTestPaper as etp 
inner join OLTR_StudyStudentRCourse as rc on etp.CourseID=rc.CourseID 
inner join OLTR_StudySubjectRCourse as src on etp.CourseID=src.CourseID 
inner join OLTR_StudyProjectRSubject as rs on src.SubjectID=rs.SubjectID 
inner join OLTR_StudyProject as pj on rs.ProjectID=pj.ProjectID and etp.PaperAgain=1 
and (StartTime <= getdate() and getdate() <= Endtime )
where rc.tag<>1 and rc.CourseID not in(select distinct pr.CourseID 
from OLTR_ExamPaperRecard as pr) and rc.StudentID='S08030012' and rs.ProjectID='P08120001'

我想要得到count()的值.我想得到1 ，却出来6 ，如何是好a 加distinct也不行！！！！????????

[lizhengnan]

distinct不会影响count.

你不用COUNT不行吗.

用DATATABLE.ROWS.COUNT来显示记录的条数.

[cyz9977]

在使用join時候的注意點：
如果只要使用join的表中某個或幾個字段，就不要join整個表！！！！

select  distinct Count(pj.ProjectID) from OLTR_ExamTestPaper as etp 
inner join (select distinct CourseID from OLTR_StudyStudentRCourse) as rc on etp.CourseID=rc.CourseID 
inner join (select distinct CourseID from OLTR_StudySubjectRCourse) as src on etp.CourseID=src.CourseID 
inner join (select distinct subjectid from OLTR_StudyProjectRSubject) as rs on src.SubjectID=rs.SubjectID 
inner join (select distinct ProjectID from OLTR_StudyProject as pj on rs.ProjectID=pj.ProjectID and etp.PaperAgain=1 
and (StartTime <= getdate() and getdate() <= Endtime )
where rc.tag<>1 and rc.CourseID not in(select distinct pr.CourseID 
from OLTR_ExamPaperRecard as pr) and rc.StudentID='S08030012' and rs.ProjectID='P08120001'

[bjwtufv]

mark

[cow8063]

那你使用distinct不就行了？

重复是来自一个表还是多个表？

left join?

[jy00251278]

sql 里用count读数
C# 里用tables[i].rows.count

[Ny-6000]

just like layer two