SQL 将一个字段内用逗号分隔的内容分成多条记录

转自：http://www.cnblogs.com/zfanlong1314/archive/2013/01/14/2859848.html

 --> 测试数据

 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
 */