下面程序出现无法绑定由多个部分组成的标识符 "a.tcid",求解决
use school_MS
go
create procedure ProcAvg
(@sname nvarchar(20),@cname nvarchar(20),@score int output)
as
begin
select @score=score
from student_course a join course b join student c
on b.cno=a.tcid
on a.sno=c.sno
where sname=@sname AND cname=@cname
end
go