//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