select a.Bjbh,a.Sbdw,b.Xmmc,c.Clhj from (dbo.Yw_RegCase a inner join dbo.Sz_Services b ON a.servicesid = b.id) join (dbo.Yw_RegCase a inner join dbo.Yw_CaseProcess c ON a.Bjzt = c.Bjzt) on (a.cjsj between DATEADD(dayofyear, - 30, GETDATE()) and GETDATE()) order by a.cjsj

出错: 在 FROM 子句中多次指定了相关名称 'a'。

请帮忙指点一下，谢谢！

应该是这样的：select a.Bjbh,a.Sbdw,b.Xmmc,c.Clhj from Yw_RegCase a inner join dbo.Sz_Services b ON a.servicesid = b.id inner join dbo.Yw_CaseProcess c ON a.Bjzt = c.Bjzt where (a.cjsj between DATEADD(dayofyear, - 30, GETDATE()) and GETDATE()) order by a.cjsj

where (a.cjsj between DATEADD(dayofyear, - 30, GETDATE()) and GETDATE())
这个位置不太对，where后面的列名呢？要不就是你的括号写的不对多了一个吧？
是不是这样？
where a.cjsj between DATEADD(dayofyear, - 30, GETDATE()) and GETDATE()