各位大侠，如果我的数据库表是如下形式的
编号ID 类型type 地点Point_ID 值value 时间
1 温度 1 30 2012-5-1
2 湿度 1 50 2012-5-1
3 温度 2 35 2012-5-1
想要把同一类型、同一地点、同一时间的值在视图中用一条记录显示，如下：
编号 温度 湿度 地点 时间
1 30 50 1 2012-5-1
2 35 2 2012-5-1
请问哪位大侠知道sql语句应该怎么写？
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- SQL code
select ID 编号, max(case [type] when '温度' then [value] else 0 end) 温度, max(case [type] when '湿度' then [value] else 0 end) 湿度, Point_ID 地点, [Time] 时间from yourtablegroup by ID,Point_ID,[Time]
------解决方案--------------------
看看是不是你想要的
- SQL code
use tempdb go--创建测试表create table test( ID int, --编号ID [Type] varchar(10),--类型 Point_ID int,--地点 Value int,--值 [DateTime] datetime--时间);--插入测试数据insert into test values(1,'温度',1,30,'2012-5-1');insert into test values(1,'湿度',1,50,'2012-5-1')insert into test values(1,'温度',2,35,'2012-5-1')select * from testSELECT id ,MAX(CASE type WHEN '温度' THEN Value ELSE 0 END ) '温度',MAX(CASE type WHEN '湿度' THEN Value ELSE 0 END ) '湿度' ,Point_ID,[DateTime]FROM testGROUP BY id ,Point_ID,[DateTime]
------解决方案--------------------
- SQL code
--行列互转--摘自中国风博客，引用请标明内容来源--1、行换列if object_id('Class') is not null drop table ClassGoCreate table Class([Student] nvarchar(2),[Course] nvarchar(2),[Score] int)Insert Classselect N'张三',N'语文',78 union allselect N'张三',N'数学',87 union allselect N'张三',N'英语',82 union allselect N'张三',N'物理',90 union allselect N'李四',N'语文',65 union allselect N'李四',N'数学',77 union allselect N'李四',N'英语',65 union allselect N'李四',N'物理',85 Go--2000方法:--动态:declare @s nvarchar(4000)set @s=''Select @[email protected]+','+quotename([Course])+'=max(case when [Course]=' +quotename([Course],'''')+' then [Score] else 0 end)'from Class group by[Course]--select @sexec('select [Student][email protected]+' 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]select @sexec('select * from Class pivot (max([Score]) for [Course] in([email protected]+'))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 @[email protected]+','+quotename([Course])+'=max(case when [Course]='+quotename([Course],'''')+'then [Score] else 0 end)'from Class group by[Course]exec('select [Student][email protected]+',[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]=([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+',','') [email protected]exec('select [Student],[email protected]+',[总成绩] from (select *,[总成绩]=sum([Score])over(partition by [Student]) from Class) a pivot (max([Score]) for [Course] in([email protected]+'))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 if not object_id('Class') is null drop table ClassGoCreate table Class([Student] nvarchar(2),[数学] int,[物理] int,[英语] int,[语文] int)Insert Classselect N'李四',77,85,65,65 union allselect N'张三',87,90,82,78Go--2000:动态:declare @s nvarchar(4000)select @s=isnull(@s+' union all ','')+'select [Student],[Course]='+quotename(Name,'''')--isnull(@s+' union all ','') [email protected] 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 Colidexec('select * from ([email protected]+')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 Colidexec('select Student,[Course],[Score] from Class unpivot ([Score] for [Course] in([email protected]+'))b')goselect 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*/--行列互换问题，方法自己选合适的