假设我有以下简单的表变量:
declare @databases table
(
DatabaseID int,
Name varchar(15),
Server varchar(15)
)
-- insert a bunch rows into @databases
如果我想遍历各行，声明和使用游标是我唯一的选择吗?还有别的办法吗?
当前回答
这将在SQL SERVER 2012版本中工作。
declare @Rowcount int
select @Rowcount=count(*) from AddressTable;
while( @Rowcount>0)
begin
select @Rowcount=@Rowcount-1;
SELECT * FROM AddressTable order by AddressId desc OFFSET @Rowcount ROWS FETCH NEXT 1 ROWS ONLY;
end
其他回答
Step1:下面的select语句为每条记录创建一个具有唯一行号的临时表。
select eno,ename,eaddress,mobno int,row_number() over(order by eno desc) as rno into #tmp_sri from emp
步骤2:声明所需的变量
DECLARE @ROWNUMBER INT
DECLARE @ename varchar(100)
步骤3:从临时表中获取总行数
SELECT @ROWNUMBER = COUNT(*) FROM #tmp_sri
declare @rno int
Step4:根据在temp中创建的唯一行号循环temp表
while @rownumber>0
begin
set @rno=@rownumber
select @ename=ename from #tmp_sri where rno=@rno **// You can take columns data from here as many as you want**
set @rownumber=@rownumber-1
print @ename **// instead of printing, you can write insert, update, delete statements**
end
SELECT @pk = @pk + 1
会更好:
SET @pk += @pk
避免使用SELECT如果你没有引用表，只是分配值。
你可以使用while循环:
While (Select Count(*) From #TempTable) > 0
Begin
Insert Into @Databases...
Delete From #TempTable Where x = x
End
如果您别无选择，只能逐行创建FAST_FORWARD游标。它和构建while循环一样快，而且更容易长期维护。
FAST_FORWARD 指定一个启用性能优化的FORWARD_ONLY、READ_ONLY游标。如果还指定了SCROLL或FOR_UPDATE，则FAST_FORWARD不能指定。
-- [PO_RollBackOnReject] 'FININV10532'
alter procedure PO_RollBackOnReject
@CaseID nvarchar(100)
AS
Begin
SELECT *
INTO #tmpTable
FROM PO_InvoiceItems where CaseID = @CaseID
Declare @Id int
Declare @PO_No int
Declare @Current_Balance Money
While (Select ROW_NUMBER() OVER(ORDER BY PO_LineNo DESC) From #tmpTable) > 0
Begin
Select Top 1 @Id = PO_LineNo, @Current_Balance = Current_Balance,
@PO_No = PO_No
From #Temp
update PO_Details
Set Current_Balance = Current_Balance + @Current_Balance,
Previous_App_Amount= Previous_App_Amount + @Current_Balance,
Is_Processed = 0
Where PO_LineNumber = @Id
AND PO_No = @PO_No
update PO_InvoiceItems
Set IsVisible = 0,
Is_Processed= 0
,Is_InProgress = 0 ,
Is_Active = 0
Where PO_LineNo = @Id
AND PO_No = @PO_No
End
End
