一些有用的SQL語句

1)從部門主管是張三往上找，下面找2階。如果去掉Step的限制就可以抓取所有的階

with cte as
(
select *,1 as step from HRDepartment where MasterName='趙三'
union all
select a.*,b.step+1 as step from HRDepartment as a,cte as b where a.DepartmentCode=b.ParentCode
)
select * from cte where step<=2

2)行轉列，列轉行的做法

create table #t1(
     name varchar(10),
     stID int,
     math float,
     English float
)
insert #t1 values('A1',1,10.1,20.2)
insert #t1 values('A2',2,30.3,40.4)

SELECT P.name,P.stID,P.className,P.ClassNo
into #t2
FROM 
(
    SELECT name,stID, math, English
     FROM #t1
)T
UNPIVOT  
(
    ClassNo  FOR className IN
    ( math, English )
) P
select * from #t2

select * from #t2 pivot(max(ClassNo) for className in (math,English))a


drop table #t2
drop table #t1