表A
id name 主板 CPU 内存
1 联想 945 C1.6 DDR 1G
2 方正 845 C2.0 DDR 2G 求一SQL语句将表A分解为主从表(表B表C):
结果如下:
表B
id name
1 联想
2 方正表C
id tname model
1 主板 945
1 CPU C1.6
1 内存 DDR 1G
2 主板 845
2 CPU C2.0
2 内存 DDR 2G
id name 主板 CPU 内存
1 联想 945 C1.6 DDR 1G
2 方正 845 C2.0 DDR 2G 求一SQL语句将表A分解为主从表(表B表C):
结果如下:
表B
id name
1 联想
2 方正表C
id tname model
1 主板 945
1 CPU C1.6
1 内存 DDR 1G
2 主板 845
2 CPU C2.0
2 内存 DDR 2G
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'
GoSQL2000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
*/
-- Author: liangCK 小梁
-- Date : 2008-12-08 16:14:05
---------------------------------
--> 生成测试数据: @T
DECLARE @T TABLE (id INT,name VARCHAR(4),主板 VARCHAR(20),CPU VARCHAR(4),内存 VARCHAR(5))
INSERT INTO @T
SELECT 1,'联想','945','C1.6','DDR1G' UNION ALL
SELECT 2,'方正','845','C2.0','DDR2G'--SQL查询如下:SELECT id,name
FROM @TSELECT
id,'主板' AS tname,
主板 AS model
FROM @T
UNION ALL
SELECT
id,'CPU' AS tname,
CPU AS model
FROM @T
UNION ALL
SELECT
id,'内存' AS tname,
内存 AS model
FROM @T
ORDER BY id/*
id name
----------- ----
1 联想
2 方正(2 行受影响)id tname model
----------- ----- --------------------
1 主板 945
1 CPU C1.6
1 内存 DDR1G
2 内存 DDR2G
2 CPU C2.0
2 主板 845(6 行受影响)
*/
INSERT @TB
SELECT 1, N'联想', '945', 'C1.6', 'DDR 1G' UNION ALL
SELECT 2, N'方正', '845', 'C2.0', 'DDR 2G'SELECT ID,NAME FROM @TB
/*
ID NAME
----------- ----------
1 联想
2 方正
*/
SELECT ID,N'主板' AS tname,主板 as model FROM @TB UNION ALL
SELECT ID,N'CPU' ,cpu FROM @TB UNION ALL
SELECT ID,N'内存', 内存 FROM @TB ORDER BY ID
/*
ID tname model
----------- ----- ----------
1 主板 945
1 CPU C1.6
1 内存 DDR 1G
2 内存 DDR 2G
2 CPU C2.0
2 主板 845
*/
union all
select tname = 'CPU' , model = CPU from A
union all
select tname = '内存' , model = 内存 from A