MYSQL--case when用法

1.

  
  
  
  

   
   
   
   
select name, 
   
   
   
   
 case 
   
   
   
   
 when birthday<'1981' then 'old' 
   
   
   
   
 when birthday>'1988' then 'yong' 
   
   
   
   
 else 'ok' END YORN 
   
   
   
   
from lee; 
  
  
  
  

2.

  
  
  
  

   
   
   
   
select NAME, 
   
   
   
   
 case name 
   
   
   
   
 when 'sam' then 'yong' 
   
   
   
   
 when 'lee' then 'handsome' 
   
   
   
   
 else 'good' end 
   
   
   
   
from lee; 
  
  
  
  

もちろんcase when文は再結合できます
3.

  
  
  
  

   
   
   
   
select name,birthday, 
   
   
   
   
 case 
   
   
   
   
 when birthday>'1983' then 'yong' 
   
   
   
   
 when name='lee' then 'handsome' 
   
   
   
   
 else 'just so so ' end 
   
   
   
   
from lee; 
   
   
   
   
 
  
  
  
  

以上mysqlのcase when文の使用例を説明します.