检查一个表中的2个主键

Question

我有表psc_Pro_ProfessorPositions（ProfessorID，PositionID，StartDate，EndDate）。它有2个主键是ProfessorID，PositionID。

我想检查一下ProfessorID，我不想在表格中插入PositionID。我写的是这样的：

插入CoreUIs.dbo.psc_Pro_ProfessorPositions     （         ProfessorID，PositionID，开始日期，结束日期     ）

select a.MaQuanLy,b.MaQuanLy,convert(smalldatetime,NgayHieuLuc),convert(smalldatetime,NgayHetHieuLuc) 

from inserted

inner join GiangVien a on a.MaGiangVien = inserted.MaGiangVien
inner join ChucVu b on b.MaChucVu = inserted.MaChucVu
where a.MaQuanLy not in (select ProfessorID  from CoreUIs.dbo.psc_Pro_ProfessorPositions)
and b.MaQuanLy not in (select PositionID  from CoreUIs.dbo.psc_Pro_ProfessorPositions)

但这是错的。可以帮帮我吗？谢谢大家。

Answer 1

;WITH x AS
(
  SELECT TeacherID, ClassID, ClassStuID, s = [SUM],
    rn = ROW_NUMBER() OVER (PARTITION BY TeacherID ORDER BY ClassID)
  FROM dbo.TB1
)
SELECT TeacherID, ClassID, ClassStuID, 
  [SUM] = CASE rn WHEN 1 THEN s ELSE NULL END
FROM x
ORDER BY TeacherID, [SUM] DESC;

Answer 2

您可以使用带有ROW_NUMBER（）OVER（）的CTE来识别每个TeacherID的第一行：

; with a as (
    select * from TB1
    union
    select * from TB2
)
, b as (
    select *, r=ROW_NUMBER()over(partition by a.TeacherID order by a.TeacherID, 
    a.ClassID, a.ClassStuID) from a
)
select b.TeacherID, b.ClassID, b.ClassStuID
, [SUM]=case b.r when 1 then b.[SUM] else null end
from b
order by b.TeacherID, b.r
go

结果：