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SQL Server学习——行列互转

SQL Server 作者:jiaoleifuck 时间:2011-04-14 18:14:44 0 删除 编辑
--行列互转


--1、行互列
--生成测试数据

if not object_id('Class') is null
drop table Class
Go
Create table Class([Student] nvarchar(2),[Course] nvarchar(2),[Score] int)
Insert Class
select N'张三',N'语文',78 union all
select N'张三',N'数学',87 union all
select N'张三',N'英语',82 union all
select N'张三',N'物理',90 union all
select N'李四',N'语文',65 union all
select N'李四',N'数学',77 union all
select N'李四',N'英语',65 union all
select N'李四',N'物理',85
Go
--2000方法:
动态:

declare @s nvarchar(4000)
set @s=''
Select @s=@s+','+quotename([Course])+'=max(case when [Course]='+quotename([Course],'''')+' then [Score] else 0 end)'
from Class group by[Course]
exec('select [Student]'+@s+' from Class group by [Student]')


生成静态:

select
[Student],
[数学]=max(case when [Course]='数学' then [Score] else 0 end),
[物理]=max(case when [Course]='物理' then [Score] else 0 end),
[英语]=max(case when [Course]='英语' then [Score] else 0 end),
[语文]=max(case when [Course]='语文' then [Score] else 0 end)
from
Class
group by [Student]

GO
动态:

declare @s nvarchar(4000)
Select @s=isnull(@s+',','')+quotename([Course]) from Class group by[Course]
exec('select * from Class pivot (max([Score]) for [Course] in('+@s+'))b')

生成静态:
select *
from
Class
pivot
(max([Score]) for [Course] in([数学],[物理],[英语],[语文]))b

生成格式:


------------------------------------------------------------------------------------------
go
--加上总成绩(学科平均分)

--2000方法:
动态:

declare @s nvarchar(4000)
set @s=''
Select @s=@s+','+quotename([Course])+'=max(case when [Course]='+quotename([Course],'''')+' then [Score] else 0 end)'
from Class group by[Course]
exec('select [Student]'+@s+',[总成绩]=sum([Score]) from Class group by [Student]')--加多一列(学科平均分用avg([Score]))

生成动态:

select
[Student],
[数学]=max(case when [Course]='数学' then [Score] else 0 end),
[物理]=max(case when [Course]='物理' then [Score] else 0 end),
[英语]=max(case when [Course]='英语' then [Score] else 0 end),
[语文]=max(case when [Course]='语文' then [Score] else 0 end),
[总成绩]=sum([Score]) --加多一列(学科平均分用avg([Score]))
from
Class
group by [Student]

go

--2005方法:

动态:

declare @s nvarchar(4000)
Select @s=isnull(@s+',','')+quotename([Course]) from Class group by[Course] --isnull(@s+',','') 去掉字符串@s中第一个逗号
exec('select [Student],'+@s+',[总成绩] from (select *,[总成绩]=sum([Score])over(partition by [Student]) from Class) a
pivot (max([Score]) for [Course] in('+@s+'))b ')

生成静态:

select
[Student],[数学],[物理],[英语],[语文],[总成绩]
from
(select *,[总成绩]=sum([Score])over(partition by [Student]) from Class) a --平均分时用avg([Score])
pivot
(max([Score]) for [Course] in([数学],[物理],[英语],[语文]))b

生成格式:



go

--2、列转行
--> --> (Roy)生成测试数据

if not object_id('Class') is null
drop table Class
Go
Create table Class([Student] nvarchar(2),[数学] int,[物理] int,[英语] int,[语文] int)
Insert Class
select N'李四',77,85,65,65 union all
select N'张三',87,90,82,78
Go

--2000:

动态:

declare @s nvarchar(4000)
select @s=isnull(@s+' union all ','')+'select [Student],[Course]='+quotename(Name,'''')--isnull(@s+' union all ','') 去掉字符串@s中第一个union all
+',[Score]='+quotename(Name)+' from Class'
from syscolumns where ID=object_id('Class') and Name not in('Student')--排除不转换的列
order by Colid
exec('select * from ('+@s+')t order by [Student],[Course]')--增加一个排序

生成静态:
select *
from (select [Student],[Course]='数学',[Score]=[数学] from Class union all
select [Student],[Course]='物理',[Score]=[物理] from Class union all
select [Student],[Course]='英语',[Score]=[英语] from Class union all
select [Student],[Course]='语文',[Score]=[语文] from Class)t
order by [Student],[Course]

go
--2005:

动态:

declare @s nvarchar(4000)
select @s=isnull(@s+',','')+quotename(Name)
from syscolumns where ID=object_id('Class') and Name not in('Student')
order by Colid
exec('select Student,[Course],[Score] from Class unpivot ([Score] for [Course] in('+@s+'))b')

go
select
Student,[Course],[Score]
from
Class
unpivot
([Score] for [Course] in([数学],[物理],[英语],[语文]))b

生成格式:

<!-- 正文结束 -->

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/21339399/viewspace-1118041/,如需转载,请注明出处,否则将追究法律责任。

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注册时间:2009-04-09