sql条件查询语句的简单实例

代码如下:

//创建成绩表 
create table result( 
       stu_id varchar2(20) not null, 
       china number(9,2) null, 
       math number(9,2) null, 
       english number(9,2) null
); 

//插入数据 
insert into result values('0001',60,20,80); 
insert into result values('0002',80,60,80); 
insert into result values('0003',20,85,80); 
select *from result; 

//条件查询 
select  stu_id,(case 
         when china>80 then '优秀' 
         when china>=60 then '及格' 
         when china<60 then  '不及格' 
         end) as 语文 , 
      (case 
         when math>80 then '优秀' 
         when math>=60 then '及格' 
         when math<60 then '不及格' 
       end )as 数学 , 
         (case 
         when english>80 then '优秀' 
         when english>=60 then '及格' 
         when english<60 then '不及格' 
       end) as 英语 
from result