sql不常用函數總結以及事務，增加，刪除觸發器
distinct 刪除重復行
declare @x 申明一個變量
convert(varchar(20),tscore.tenglish) 類型轉換
cast(xx as varchar(10)) 類型轉換
www.jb51.net
======================================================
情況
case
when xxx then xx
when xxxx then xxxxx
else
end
=======================================================
while xxx
begin
xxxxxx
end
www.jb51.net
事務
===================================================
begin tran
declare @sum int = 0
update bank set balance=balance-1000 where cid='0001'
set @sum=@sum+@@error
update bank set balance=balance + 1000 where cid='0002'
set @sum=@sum+@@error
if @sum<>0
begin
rollback
print '回滾！'
end
else
begin
--提交事務
commit tran
print '提交了！'
end
===================================================
begin tran www.jb51.net
begin try
declare @sum int = 0
update bank set balance=balance-900 where cid='0001'
set @sum=@sum+@@error
update bank set balance=balance + 900 where cid='0002'
set @sum=@sum+@@error
commit
end try
begin catch
rollback
end catch
=====================================================
declare @halfCount int= ceiling(@count/2.0) 向上
增加時觸發器
=========================================
create trigger tri_TblClass_insert_after
on TblClass after insert
as
begin
declare @id int
declare @name varchar(50)
declare @desc varchar(50)
select @id=tclassId,@name=tclassname,@desc=tclassdesc from inserted
print @id
print @name
print @desc
end www.jb51.net
=========================================
刪除時觸發器
create trigger tri_TblClass_delete_after
on TblClass instead of delete
as
begin
insert into TblClassBak
select * from deleted
end
========================================
作者 xhccom
