sql 循環語句幾種方式

 

--第一

 

declare @orderNum varchar(255)

create table #ttableName(id int identity(1,1),Orders varchar(255))

declare @n int,@rows int

insert #ttableName(orders) select orderNum from pe_Orders where orderId<50

--select @rows=count(1) from pe_Orders

select @rows =@@rowcount 

set @n=1 

while @n<=@rows

begin

select @orderNum=OrderNum from PE_Orders where OrderNum=(select Orders from #ttableName where id=@n)

print (@OrderNum)

select @n=@n+1

end

drop table #ttableName

 

 

--第二

 

declare @orderN varchar(50)--臨時變量，用來保存遊標值

declare y_curr cursor for --申明遊標 爲orderNum

select orderNum from pe_Orders where orderId<50

open y_curr --打開遊標

fetch next from Y_curr into @orderN ----開始循環遊標變量

while(@@fetch_status=0)---返回被 FETCH  語句執行的最後遊標的狀態，而不是任何當前被鏈接打開的遊標的狀態。

begin

print (@orderN)

update pe_Orders set Functionary+@orderN where orderNum=@orderN --操做數據庫

fetch next from y_curr into @orderN --開始循環遊標變量

end

close y_curr--關閉遊標

deallocate y_curr --釋放遊標

 

--第三

select orderNum,userName,MoneyTotal into #t from pe_Orders po 

DECLARE @n int,@error int

--set @n=1 

set @error=0

BEGIN TRAN --申明事務

declare @orderN varchar(50),@userN varchar(50) --臨時變量，用來保存遊標值

declare y_curr cursor for  --申明遊標 爲orderNum,userName

select orderNum,userName from PE_Orders where Orderid<50

open y_curr

fetch next from y_curr into @orderN,@userN

while @@fetch_status = 0

BEGIN

select isnull(sum(MoneyTotal),0),orderNum from #t where username=@userN

-- set @n=@n+1

set @error=@error+@@error--記錄每次運行sql後 是否正確  0正確

fetch next from y_curr into @orderN,@userN

END

IF @error=0

BEGIN

commit tran --提交

END

ELSE

BEGIN

ROLLBACK TRAN --回滾

END

close y_curr

deallocate y_curr

DROP TABLE #t

 

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轉自http://www.cnblogs.com/Luouy/archive/2012/05/11/2495394.html