Question

我想将DriverID表的Driver列设置为5000,5001，....

为此，我写了这个脚本：

use WeighbridgeDB
GO

DECLARE @NewDriverID int;
SET @NewDriverID = 5000;

DECLARE Driver_Cursor CURSOR FOR 
SELECT DriverID FROM Driver
FOR UPDATE;

OPEN Driver_Cursor;

FETCH NEXT FROM Driver_Cursor

WHILE @@FETCH_STATUS = 0
BEGIN
    UPDATE Driver SET DriverID = @NewDriverID WHERE CURRENT OF Driver_Cursor;
    SET @NewDriverID += 1;
    FETCH NEXT FROM Driver_Cursor
END

CLOSE Driver_Cursor;
DEALLOCATE Driver_Cursor;
GO

但是While循环不会停止，@@FETCH_STATUS的值始终为0.我认为Cursor重建自己，因为更新发生在表或其他东西上。

如何纠正这种情况？

感谢。

Answer 1

无论如何你都不需要游标（一般来说，尝试并在TSQL中避免这些，除非极少数情况）

WITH T AS
(
SELECT *,
       ROW_NUMBER() OVER (ORDER BY DriverID) + 4999 AS NewDriverID
FROM Driver
)
UPDATE T SET DriverID = NewDriverID

Answer 2

你可以这样做：

UPDATE Driver
SET
    Driver.DriverID = d.NewDriverID 
FROM
(
    select 
        ROW_NUMBER() Over (ORDER BY DriverID) + 5000 AS NewDriverID,
        Driver.DriverID 
    from Driver 
) AS d
WHERE Driver.DriverID = p.DriverID

几乎没有理由使用光标。

在SQL Server 2008中更新结果行时不会停止CURSOR循环

2 个答案: