那位高手请帮帮我

是否可以以某一列为依据将一行分解为多行的SQL语句? 
举例如下: 
表X(a,b,c) 
a b c 
--------------------- 
1 x+y t1 
2 q+w+e t2 
3 z+aa+bb+cc+dd t3 
... 

按b列以+号分解,+号的个数不定,得到下表 
a b c 
---------- 
1 x t1 
1 y t1 
2 q t2 
2 w t2 
2 e t2 
3 z t3 
3 aa t3 
3 bb t3 
3 cc t3 
3 dd t3 

SQL code

--> --> (Roy)生成測試數據
 
if not object_id('X') is null
    drop table X
Go
Create table X([a] int,[b] nvarchar(13),[c] nvarchar(2))
Insert X
select 1,N'x+y',N't1' union all
select 2,N'q+w+e',N't2' union all
select 3,N'z+aa+bb+cc+dd',N't3'
Go
Select 
a.a,[b]=substring(a.b,b.number,charindex('+',a.b+'+',b.number)-b.number),a.c 
from X as a,master.dbo.spt_values as b
where b.type='P' and substring('+'+a.[b],b.number,1)='+'

/*
a    b    c
1    x    t1
1    y    t1
2    q    t2
2    w    t2
2    e    t2
3    z    t3
3    aa    t3
3    bb    t3
3    cc    t3
3    dd    t3
*/

SQL code

其它方法参照

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)=','


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,charindex(',',Split)-1) as nvarchar(100)),Split= cast(stuff(Split,1,charindex(',',Split),'') as nvarchar(100)) from Roy where split>''
)
select COl1,COl2 from roy order by COl1 option (MAXRECURSION 0)

生成结果:
/*
Col1        COl2
----------- -----
1           a
1           b
1           c
2           d
2           e
3           f
*/