/****************************************************************************************************************************************************** 
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(' <Tab> 
                {for $i in /Tab[position() <last()]/@COl2 return concat(string($i),",")} 
                {concat("",string(/Tab[last()]/@COl2))} 
                </Tab>') 
                )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) 
*/ 


--参考
拆分表:

--> --> (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(5))
Insert Tab
select 1,N'a,b,c' union all
select 2,N'd,e' union all
select 3,N'f'
Go

--SQL2000用辅助表:
if object_id('Tempdb..#Num') is not null
    drop table #Num
go
select top 100 ID=Identity(int,1,1) into #Num from syscolumns a,syscolumns b
Select 
    a.Col1,COl2=substring(a.Col2,b.ID,charindex(',',a.Col2+',',b.ID)-b.ID) 
from 
    Tab a,#Num b
where
    charindex(',',','+a.Col2,b.ID)=b.ID --也可用 substring(','+a.COl2,b.ID,1)=','
--2000不使用辅助表
Select
    a.Col1,COl2=substring(a.Col2,b.number,charindex(',',a.Col2+',',b.number)-b.number) 
from 
    Tab a join master..spt_values  b 
    ON B.type='p' AND B.number BETWEEN 1 AND LEN(A.col2)
where
     substring(','+a.COl2,b.number,1)=','


SQL2005用Xml:

select 
    a.COl1,b.Col2
from 
    (select Col1,COl2=convert(xml,'<root><v>'+replace(COl2,',','</v><v>')+'</v></root>') from Tab)a
outer apply
    (select Col2=C.v.value('.','nvarchar(100)') from a.COl2.nodes('/root/v')C(v))b




SQL05用CTE:

;with roy as 
(select Col1,COl2=cast(left(Col2,charindex(',',Col2+',')-1) as nvarchar(100)),Split=cast(stuff(COl2+',',1,charindex(',',Col2+','),'') as nvarchar(100)) from Tab
union all
select Col1,COl2=cast(left(Split,c