复制代码 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