Question

以下T-SQL代码段有效，但我想知道是否有更聪明和/或更简洁的方法来完成两个不同行之间的字段值交换。（为简单起见，代码具有硬编码的pkey值。）

BEGIN TRAN;

declare @swapFormSeqA int;
declare @swapFormSeqB int;

SELECT @swapFormSeqA = DisplaySeq
FROM CustomCatalogForm
WHERE CustomCatalogFormId = 1;

SELECT @swapFormSeqB = DisplaySeq
FROM CustomCatalogForm
WHERE CustomCatalogFormId = 2;

UPDATE CustomCatalogForm
SET DisplaySeq = @swapFormSeqB
WHERE CustomCatalogFormId = 1;

UPDATE CustomCatalogForm
SET DisplaySeq = @swapFormSeqA
WHERE CustomCatalogFormId = 2;

COMMIT TRAN;

编辑：我特意使用Sql2k5，因此2k8不是一个选项。

Answer 1

你可以这样做：

begin tran

declare @sum int

select @sum = sum(DisplaySeq)
from CustomCatalogForm
where CustomCatalogFormId in (1,2)

update CustomCatalogForm
set DisplaySeq = @sum - DisplaySeq
where CustomCatalogFormId in (1,2)

commit tran

Answer 2

像这样：

UPDATE CustomCatalogForm
SET DisplaySeq = (SELECT DisplaySeq
    FROM CustomCatalogForm T2
    WHERE T2.CustomCatalogFormId =
        -1*(CustomCatalogForm.CustomCatalogFormId -2) +1
    )
WHERE CustomCatalogFormId IN (1,2);

（警告：请先测试一下，因为我无法从这里测试）。

Answer 3

假设您的表格如下：

--drop table CustomCatalogForm
create table CustomCatalogForm
 (
    CustomCatalogFormId  int  not null
   ,DisplaySeq char(1) not null
 )

insert CustomCatalogForm (CustomCatalogFormId, DisplaySeq)
 values (1,'A')
insert CustomCatalogForm (CustomCatalogFormId, DisplaySeq)
 values (2,'B')
insert CustomCatalogForm (CustomCatalogFormId, DisplaySeq)
 values (3,'C')
insert CustomCatalogForm (CustomCatalogFormId, DisplaySeq)
 values (4,'D')

然后这将对任何两个给定值（我用2和3测试）进行：

select * from CustomCatalogForm
-------------------------------
DECLARE
  @Item1 int
 ,@Item2 int

SET @Item1 = 2
SET @Item2 = 3

UPDATE CustomCatalogForm
 set DisplaySeq = ccf2.DisplaySeq
 from CustomCatalogForm ccf
  inner join (select CustomCatalogFormId, DisplaySeq
               from CustomCatalogForm
               where CustomCatalogFormId = @Item1
                or CustomCatalogFormId = @Item2) ccf2
   on ccf.CustomCatalogFormId <> ccf2.CustomCatalogFormId
 where ccf.CustomCatalogFormId = @Item1
  or ccf.CustomCatalogFormId = @Item2
-------------------------------
select * from CustomCatalogForm

诀窍是只在连接的两侧获取两行，并加入NOT EQUALS。

Answer 4

试试这个：

UPDATE ccf SET 
  DisplaySeq = Case CustomCatalogFormId 
     When 1 Then T2.DisplaySeq 
     When 2 Then T1.DisplaySeq  End
From CustomCatalogForm ccf 
    Join CustomCatalogForm T1 On T1.CustomCatalogFormId  = 1
    Join CustomCatalogForm T2 On T2.CustomCatalogFormId  = 2
Where ccf.CustomCatalogFormId  In (1,2)

交换两行数据之间的值

4 个答案: