日期:2014-05-18 浏览次数:20609 次
/* 标题:简单数据拆分(version 2.0) 作者:爱新觉罗.毓华(十八年风雨,守得冰山雪莲花开) 时间:2010-05-07 地点:重庆航天职业学院 描述: 有表tb, 如下: id value ----------- ----------- 1 aa,bb 2 aaa,bbb,ccc 欲按id,分拆value列, 分拆后结果如下: id value ----------- -------- 1 aa 1 bb 2 aaa 2 bbb 2 ccc */ --1. 旧的解决方法(sql server 2000) create table tb(id int,value varchar(30)) insert into tb values(1,'aa,bb') insert into tb values(2,'aaa,bbb,ccc') go --方法1.使用临时表完成 SELECT TOP 8000 id = IDENTITY(int, 1, 1) INTO # FROM syscolumns a, syscolumns b SELECT A.id, value = SUBSTRING(A.[value], B.id, CHARINDEX(',', A.[value] + ',', B.id) - B.id) FROM tb A, # B WHERE SUBSTRING(',' + A.[value], B.id, 1) = ',' DROP TABLE # --方法2.如果数据量小,可不使用临时表 select a.id , value = substring(a.value , b.number , charindex(',' , a.value + ',' , b.number) - b.number) from tb a join master..spt_values b on b.type='p' and b.number between 1 and len(a.value) where substring(',' + a.value , b.number , 1) = ',' --2. 新的解决方法(sql server 2005) create table tb(id int,value varchar(30)) insert into tb values(1,'aa,bb') insert into tb values(2,'aaa,bbb,ccc') go --方法1.使用xml完成 SELECT A.id, B.value FROM ( SELECT id, [value] = CONVERT(xml,'<root><v>' + REPLACE([value], ',', '</v><v>') + '</v></root>') FROM tb ) A OUTER APPLY ( SELECT value = N.v.value('.', 'varchar(100)') FROM A.[value].nodes('/root/v') N(v) ) B --方法2.使用CTE完成 ;with tt as (select id,[value]=cast(left([value],charindex(',',[value]+',')-1) as nvarchar(100)),Split=cast(stuff([value]+',',1,charindex(',',[value]+','),'') as nvarchar(100)) from tb union all select id,[value]=cast(left(Split,charindex(',',Split)-1) as nvarchar(100)),Split= cast(stuff(Split,1,charindex(',',Split),'') as nvarchar(100)) from tt where split>'' ) select id,[value] from tt order by id option (MAXRECURSION 0) DROP TABLE tb /* id value ----------- ------------------------------ 1 aa 1 bb 2 aaa 2 bbb 2 ccc (5 行受影响) */
------解决方案--------------------
经常用可以写一个函数.字符长度长时用函数也是一个比较好解决方法
--> --> (Roy)生成測試數據 if not object_id('Tab') is null drop table Tab Go Create table Tab([a] int,[b] nvarchar(1000)) Insert Tab select 1,N'1,2,3,1,4,5,6,7,7' union all select 1,N'2,3' union all select 2,N'1,2' union all select 2,N'2,3' union all select 3,N'1,2' union all select 3,N'2,3' Go if OBJECT_ID('fn_split','FN') is not null drop function fn_split go Create function fn_split(@a int) returns nvarchar(1000) as begin declare @s nvarchar(1000),@s2 nvarchar(1000),@i int,@split nvarchar(100) select @s=isnull(@s+',','')+b,@s2='' from Tab where a=@a select @i=charindex(',',@s),@s2=left(@s,@i),@s=replace(@s+',',@s2,''),@i=charindex(',',@s) while @i>0 begin Select @split=left(@s,@i),@s2=@s2+@split,@s=replace(@s,@split,''),@i=charindex(',',@s) end return left(@s2,len(@s2)-1) end go select [a],dbo.fn_split(a) as b from Tab group by [a] /* a b 1 1,2,3,4,5,6,7 2 1,2,3 3 1,2,3 */