合并，拆分表
--合并分拆表
/******************************************************************************************************************************************************
合并分拆表数据
整理人：中国风(Roy)
日期:2008.06.06
******************************************************************************************************************************************************/
--> --> (Roy)生成測試數據
if not object_id('Tab') is null
drop table Tab
Go
Create table Tab([Col1] int,[Col2] nvarchar(1))
Insert Tab
select 1,N'a' union all
select 1,N'b' union all
select 1,N'c' union all
select 2,N'd' union all
select 2,N'e' union all
select 3,N'f'
Go
合并表:
SQL2000用函数:
go
if object_id('F_Str') is not null
drop function F_Str
go
create function F_Str(@Col1 int)
returns nvarchar(100)
as
begin
declare @S nvarchar(100)
select @S=isnull(@S+',','')+Col2 from Tab where Col1=@Col1
return @S
end
go
Select distinct Col1,Col2=dbo.F_Str(Col1) from Tab
go
SQL2005用XML:
方法1:
select
a.Col1,Col2=stuff(b.Col2.value('/R[1]','nvarchar(max)'),1,1,'')
from
(select distinct COl1 from Tab) a
Cross apply
(select COl2=(select N','+Col2 from Tab where Col1=a.COl1 For XML PATH(''), ROOT('R'), TYPE))b
方法2:
select
a.Col1,COl2=replace(b.Col2.value('/Tab[1]','nvarchar(max)'),char(44)+char(32),char(44))
from
(select distinct COl1 from Tab) a
cross apply
(select Col2=(select COl2 from Tab where COl1=a.COl1 FOR XML AUTO, TYPE)
.query('
{for $i in /Tab[position() {concat("",string(/Tab[last()]/@COl2))}
)b SQL05用CTE: ;with roy as(select Col1,Col2,row=row_number()over(partition by COl1 order by COl1) from Tab) ,Roy2 as (select COl1,cast(COl2 as nvarchar(100))COl2,row from Roy where row=1 union all select a.Col1,cast(b.COl2+','+a.COl2 as nvarchar(100)),a.row from Roy a join Roy2 b on a.COl1=b.COl1 and a.row=b.row+1) select Col1,Col2 from Roy2 a where row=(select max(row) from roy where Col1=a.COl1) order by Col1 option (MAXRECURSION 0) 生成结果: /* Col1 COl2 ----------- ------------ 1 a,b,c 2 d,e 3 f (3 行受影响) */ 了解更多关于软件方面的知识，请访问上海软件培训学校
