Question

我正在尝试使用游标移动创建一个列，其中所有部分都等于之前的字段。例如

|  column1  |  column 2  |
|     1     |      a     |
|     2     |      b     |
|     3     |      c     |

would to go...

|  column1  |  column2  |  column3  |
|     1     |      a    |     b     |
|     2     |      b    |     c     |
|     3     |      c    |    NULL   |

所以为了做到这一点，我尝试使用基于最后一个fetch语句的游标和更新语句，如下所示：

DECLARE myCursor1 CURSOR READ_ONLY
FOR
SELECT lname AS 'lnamerecoff'
FROM testingThis
ORDER BY lname

OPEN myCursor1
DECLARE @previous char(15)
DECLARE @new char(15)

SET @previous = FETCH NEXT FROM myCursor1

IF NOT EXISTS(SELECT * FROM sys.columns WHERE name = 'lnamerecoff' 
                       AND object_id = OBJECT_ID('testingThis'))
  ALTER TABLE testingThis ADD lnamerecoff int

WHILE @@FETCH_STATUS = 0
BEGIN 
SET @new = FETCH NEXT FROM myCursor1
UPDATE testingThis
SET lnamerecoff = @new
SET @previous = @new
END

这会在我的fetch语句附近引发语法错误。谁能帮我这个？谢谢！

Answer 1

应该是：

fetch next from myCursor1 into @previous

Sql - 关于游标和变量的问题

1 个答案: