sql 循环语句几种方式

--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)--临时变量，用来保存游标值

declare y_curr cursor for --申明游标 为orderNum

select orderNum from pe_Orders where orderId<50

open y_curr --打开游标

fetch next from Y_curr into @orderN ----开始循环游标变量

while(@@fetch_status=0)---返回被 FETCH  语句执行的最后游标的状态，而不是任何当前被连接打开的游标的状态。

begin

print (@orderN)

update pe_Orders set Functionary+@orderN where orderNum=@orderN --操作数据库

fetch next from y_curr into @orderN --开始循环游标变量

end

close y_curr--关闭游标

deallocate y_curr --释放游标

--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 --申明事务

declare @orderN varchar(50),@userN varchar(50) --临时变量，用来保存游标值

declare y_curr cursor for  --申明游标 为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--记录每次运行sql后 是否正确  0正确

fetch next from y_curr into @orderN,@userN

END

IF @error=0

BEGIN

commit tran --提交

END

ELSE

BEGIN

ROLLBACK TRAN --回滚

END

close y_curr

deallocate y_curr

DROP TABLE #t