--合并
--生成测试数据
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
如何合并成如下结果，之间论坛有过不止一贴了，这里不再重述
Col1 COl2
----------- ------------
1 a,b,c
2 d,e
3 f
*********************分割线****************************
拆分:
方法1：使用临时表
--生成测试数据
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
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)=','
/*
Col1 COl2
----------- -----
1 a
1 b
1 c
2 d
2 e
3 f
*/
方法2：使用XML
--生成测试数据
DECLARE @t TABLE( ID INT IDENTITY, data VARCHAR(50))
INSERT INTO @t(data) SELECT 'AA,AB,AC,AD'
INSERT INTO @t(data) SELECT 'BA,BB,BC'
SELECT * FROM @t
DECLARE @t TABLE( ID INT IDENTITY, data VARCHAR(50))
INSERT INTO @t(data) SELECT 'AA,AB,AC,AD'
INSERT INTO @t(data) SELECT 'BA,BB,BC'
SELECT F1.id,
F1.data,
O.splitdata
FROM
(
SELECT *,
cast('<X>'+replace(F.data,',','</X><X>')+'</X>' as XML) as xmlfilter from @t F
)F1
CROSS APPLY
(
SELECT fdata.D.value('.','varchar(50)') as splitdata
FROM f1.xmlfilter.nodes('X') as fdata(D)) O
