SQL 将一个字段内用逗号分隔的内容分成多条记录

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本文转http://www.mhzg.net/a/20117/2011789260293.html

由于业务需求，我们可能会把一串以分割符字符串数据放到一个字段，如我们在客户端处理拆分是很简单的，不过这样做效果不太好，怎么用SQL SERVER 2008 来解决这件事件哪？

--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)=','

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
*/