SQL Server- 行列转换 行转列，多行转多列 - max 函数用法

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效果如图，把同一个 code， 按 cate 列分为 Actual 和 Budget 两行，再把mode 每种类型转换成 列名 ，主要用到了 max 函数，很实用

 

 if exists(select * from tempdb..sysobjects where id=object_id('tempdb..#t'))
 drop table #t  
   create table #t(
     code varchar(10),
 　　cname nvarchar(30),
     fyear varchar(30),
     cate varchar(10),
     mt numeric(18,4),
     amt numeric(18,2),
     mode nvarchar(20),
     mo_mt numeric(18,4),
     mo_avgfee numeric(18,2),
     mo_rate nvarchar(20)
　　)
insert into #t 
select            '400',N'深圳','2017','Actual','280','1400','BLK',10,1,'3.57%'
 union all select '400',N'深圳','2017','Actual','280','1400','V15',20,2,'7.14%'
 union all select '400',N'深圳','2017','Actual','280','1400','V5',30,3,'10.71%'
 union all select '400',N'深圳','2017','Actual','280','1400','V0',40,4,'14.29%'
 union all select '400',N'深圳','2017','Actual','280','1400','V20',50,5,'17.86%'
 union all select '400',N'深圳','2017','Actual','280','1400','V10',60,6,'21.43%'
 union all select '400',N'深圳','2017','Actual','280','1400','V25',70,7,'25.00%'
 union all select '400',N'深圳','2018','Budget','280','0','BLK',10,1,'3.57'
 union all select '400',N'深圳','2018','Budget','280','0','V15',20,2,'7.14%'
 union all select '400',N'深圳','2018','Budget','280','0','V5',30,3,'10.71%'
 union all select '400',N'深圳','2018','Budget','280','0','V0',40,4,'14.29%'
 union all select '400',N'深圳','2018','Budget','280','0','V20',50,5,'17.86%'
 union all select '400',N'深圳','2018','Budget','280','0','V10',60,6,'21.43%'
 union all select '400',N'深圳','2018','Budget','280','0','V25',70,7,'25.00%'
 select * from #t

 --增加一个强制mode 排序，比如从 vo v1 v2 依次排序
 if exists(select * from tempdb..sysobjects where id=object_id('tempdb..#sort'))
 drop table #sort  
 　　create Table #sort  
　　(
 　　mode varchar(10),
　　)
  insert into #sort
  select distinct mode FROM #t   GROUP BY mode order by mode
  -- select * from #sort

   declare @sql nvarchar(max)     --声明一个变量
 SET @sql = '
SELECT code ' 
+',cname '
+',fyear '
+',cate ' --+ N'''类别''' 
+',isnull(mt,0) mt' -- + N'''吨数''' 
+',isnull(amt,0) amt'  -- + N'''金额''' 
select @sql = @sql + ' , max(case mode when ''' + mode+ ''' then mo_rate  else '''' end) [' + mode+ ']' 
            + ' , max(case mode when ''' + mode+ ''' then mo_avgfee  else 0 end) [' + mode+ '_unit]'
from (select  mode FROM #sort ) as a 
--print @sql 
set @sql = @sql + ' from #t group by code, cname,fyear,cate,mt,amt  order by code,fyear  ' 
print @sql   
exec(@sql)   --执行该sql