SQL 將一個字段內用逗號分隔的內容分成多條記錄

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

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

由於業務需求，我們可能會把一串以分割符字符串數據放到一個字段，如我們在客戶端處理拆分是很簡單的，不過這樣做效果不太好，怎麼用SQL SERVER 2008 來解決這件事件哪？

--參考
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用輔助表:
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)
 
生成結果:
/*
Col1        COl2
----------- -----
1           a
1           b
1           c
2           d
2           e
3           f
*/