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

我是这样做的:

declare @RowNum int, @CustId nchar(5), @Name1 nchar(25)

select @CustId=MAX(USERID) FROM UserIDs     --start with the highest ID
Select @RowNum = Count(*) From UserIDs      --get total number of records
WHILE @RowNum > 0                          --loop until no more records
BEGIN   
    select @Name1 = username1 from UserIDs where USERID= @CustID    --get other info from that row
    print cast(@RowNum as char(12)) + ' ' + @CustId + ' ' + @Name1  --do whatever

    select top 1 @CustId=USERID from UserIDs where USERID < @CustID order by USERID desc--get the next one
    set @RowNum = @RowNum - 1                               --decrease count
END

没有游标,没有临时表,没有额外的列。 USERID列必须是唯一的整数,就像大多数主键一样。

其他回答

-- [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

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

轻量级,不需要创建额外的表,如果您在表上有一个整数ID

Declare @id int = 0, @anything nvarchar(max)
WHILE(1=1) BEGIN
  Select Top 1 @anything=[Anything],@id=@id+1 FROM Table WHERE ID>@id
  if(@@ROWCOUNT=0) break;

  --Process @anything

END

我更喜欢使用偏移获取,如果你有一个唯一的ID,你可以排序你的表:

DECLARE @TableVariable (ID int, Name varchar(50));
DECLARE @RecordCount int;
SELECT @RecordCount = COUNT(*) FROM @TableVariable;

WHILE @RecordCount > 0
BEGIN
SELECT ID, Name FROM @TableVariable ORDER BY ID OFFSET @RecordCount - 1 FETCH NEXT 1 ROW;
SET @RecordCount = @RecordCount - 1;
END

这样我就不需要向表中添加字段或使用窗口函数。

可以使用游标来做到这一点:

创建函数[dbo].f_teste_loop 返回@tabela表 ( 鳕鱼int, 省varchar (10) ) 作为 开始

insert into @tabela values (1, 'verde');
insert into @tabela values (2, 'amarelo');
insert into @tabela values (3, 'azul');
insert into @tabela values (4, 'branco');

return;

end

创建过程[dbo].[sp_test_loop] 作为 开始

DECLARE @cod int, @nome varchar(10);

DECLARE curLoop CURSOR STATIC LOCAL 
FOR
SELECT  
    cod
   ,nome
FROM 
    dbo.f_teste_loop();

OPEN curLoop;

FETCH NEXT FROM curLoop
           INTO @cod, @nome;

WHILE (@@FETCH_STATUS = 0)
BEGIN
    PRINT @nome;

    FETCH NEXT FROM curLoop
           INTO @cod, @nome;
END

CLOSE curLoop;
DEALLOCATE curLoop;

end