SQL行如何转换成列？
CREATE TABLE TABLE1( ID INT , NAME VARCHAR(50))CREATE TABLE TABLE2( ID INT , USERNAME VARCHAR(50))INSERT table1SELECT 1 ,'kk' UNIONSELECT 2 ,'ll' UNIONSELECT 3 ,'ll'INSERT table2SELECT 1 ,'lk' UNIONSELECT 3, 'io' UNIONSELECT 4 ,'df'比如我用left join 得到如下结果/*t1id NAME t2id USERNAME----------- -------------------------------------------------- ----------- --------------------------------------------------1 kk 1 lk2 ll NULL NULL3 ll 3 io*/但是我想把结果换成这样id name 1 kk2 ll3 ll1 lk3 io如何实现啊，求解
--行列互转--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 @s=@s+','+quotename([Course])+'=max(case when [Course]=' +quotename([Course],'''')+' then [Score] else 0 end)'from Class group by[Course]--select @sexec('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]select @sexec('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]=([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 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 ','') 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 Colidexec('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 Colidexec('select Student,[Course],[Score] from Class unpivot ([Score] for [Course] in('+@s+'))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*/
[解决办法]
select t1id ,NAME from tbl where t1id is not null union allselect t2id ,USERNAME from tblwhere t2id is not null
[解决办法]
CREATE TABLE TABLE1( ID INT , NAME VARCHAR(50))CREATE TABLE TABLE2( ID INT , USERNAME VARCHAR(50))INSERT table1SELECT 1 ,'kk' UNIONSELECT 2 ,'ll' UNIONSELECT 3 ,'ll'INSERT table2SELECT 1 ,'lk' UNIONSELECT 3, 'io' UNIONSELECT 4 ,'df'select ID,NAME FROM(select A.ID,A.NAME,B.ID AS ID2,b.USERNAME from table1 a left join table2 b on a.id=b.ID)Munion allselect ID2,USERNAME FROM(select A.ID,A.NAME,B.ID AS ID2,b.USERNAME from table1 a left join table2 b on a.id=b.ID)nwhere ID2 is not null/*ID NAME1 kk2 ll3 ll1 lk3 io*/
[解决办法]
情况多了最好使用动态，也就是拼接查询语句
[解决办法]
SqlServer2005+中使用公用表表达式:
CREATE TABLE TABLE1( ID INT , NAME VARCHAR(50))CREATE TABLE TABLE2( ID INT , USERNAME VARCHAR(50))INSERT table1SELECT 1 ,'kk' UNIONSELECT 2 ,'ll' UNIONSELECT 3 ,'ll'INSERT table2SELECT 1 ,'lk' UNIONSELECT 3, 'io' UNIONSELECT 4 ,'df'WITH Test as(SELECT a.ID as AID,a.Name as AName,b.ID as BID,b.USERNAME AS BNameFROM TABLE1 a LEFT JOIN Table2 as bON a.ID=b.ID)SELECT AID AS ID,AName as Name FROM Test WHERE AID IS NOT NULLUNION ALL SELECT BID AS ID ,BName AS Name FROM Test WHERE BID IS NOT NULL
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神贴啊！
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