如何从表a取得以下的查询效果:(注:表a的group值不固定的,随时会变,即有可能有A,B,C;也有可能B,C,D)
假如表a如下所示:name group value
001 A 10
002 B 5
003 C 20
004 B 50
005 A 15
... ... ...那么期望的结果如下:name A B C
001 10
002 5
003 20
004 50
005 15
... ... ... ...
假如表a如下所示:name group value
001 D 10
002 E 5
003 F 20
004 F 50
005 G 15
... ... ...那么期望的结果如下:name D E F G
001 10
002 5
003 20
004 50
005 15
... ... ... ... 不知道可否实现,请高手指点。
假如表a如下所示:name group value
001 A 10
002 B 5
003 C 20
004 B 50
005 A 15
... ... ...那么期望的结果如下:name A B C
001 10
002 5
003 20
004 50
005 15
... ... ... ...
假如表a如下所示:name group value
001 D 10
002 E 5
003 F 20
004 F 50
005 G 15
... ... ...那么期望的结果如下:name D E F G
001 10
002 5
003 20
004 50
005 15
... ... ... ... 不知道可否实现,请高手指点。
/******************************************************************************************************************************************************
以学生成绩为例子,比较形象易懂整理人:中国风(Roy)日期:2008.06.06
******************************************************************************************************************************************************/--1、行互列
--> --> (Roy)生成測試數據
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:
/*
Student 数学 物理 英语 语文
------- ----------- ----------- ----------- -----------
李四 77 85 65 65
张三 87 90 82 78(2 行受影响)
*/------------------------------------------------------------------------------------------
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:/*
Student 数学 物理 英语 语文 总成绩
------- ----------- ----------- ----------- ----------- -----------
李四 77 85 65 65 292
张三 87 90 82 78 337(2 行受影响)
*/go--2、列转行
--> --> (Roy)生成測試數據
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:
/*
Student Course Score
------- ------- -----------
李四 数学 77
李四 物理 85
李四 英语 65
李四 语文 65
张三 数学 87
张三 物理 90
张三 英语 82
张三 语文 78(8 行受影响)
*/
set @sql = 'select name '
select @sql = @sql + ' , max(case group when ''' + group + ''' then value else 0 end) [' + group + ']'
from (select distinct group from tb) as a
set @sql = @sql + ' from tb group by name'
exec(@sql)
create table tb(name varchar(10),[group] varchar(10), value int)
insert into tb values('001', 'A', 10)
insert into tb values('002', 'B', 5 )
insert into tb values('003', 'C', 20)
insert into tb values('004', 'B', 50)
insert into tb values('005', 'A', 15)
godeclare @sql varchar(8000)
set @sql = 'select name '
select @sql = @sql + ' , max(case [group] when ''' + [group] + ''' then ltrim(value) else '''' end) [' + [group] + ']'
from (select distinct [group] from tb) as a
set @sql = @sql + ' from tb group by name'
exec(@sql) drop table tb/*
name A B C
---------- ------------ ------------ ------------
001 10
002 5
003 20
004 50
005 15 */
create table tb(name varchar(10),[group] varchar(10), value int)
insert into tb values('001', 'A', 10)
insert into tb values('002', 'B', 5 )
insert into tb values('003', 'C', 20)
insert into tb values('004', 'B', 50)
insert into tb values('005', 'A', 15)
go
declare @sql varchar(8000)
select @sql = isnull(@sql + '],[' , '') + [group] from tb group by [group]
set @sql = '[' + @sql + ']'
exec ('select * from (select * from tb) a pivot (max(value) for [group] in (' + @sql + ')) b')drop table tb/*
name A B C
---------- ----------- ----------- -----------
001 10 NULL NULL
002 NULL 5 NULL
003 NULL NULL 20
004 NULL 50 NULL
005 15 NULL NULL(5 行受影响)
*/