--班級表
create table CLASS
(
 ID    VARCHAR2(5) not null primary key,
 CLASSNAME VARCHAR2(10)
);
--學生表
create table STUDENT
(
 ID   VARCHAR2(10) not null primary key,
 NAME  VARCHAR2(10),
 AGE   NUMBER(3),
 CLASSID VARCHAR2(5)
);
--科目表
create table subject(
id varchar2(10) primary key,
subname varchar2(10)
);
--分數表
 create table score(
 sid varchar2(4),
 subid varchar2(10),
 score number(4,1)
);

select s1.name 姓名,
    s1.age 年齡,
    s1.classname 班級,
    score_.sid,
    數學,
    語文,
    物理,
    化學,
    (數學 + 語文 + 物理 + 化學) 總分
 from (select s.sid,
        sum(decode(s.subid, 'SUB001', s.score)) 數學,
        sum(decode(s.subid, 'SUB002', s.score)) 語文,
        sum(decode(s.subid, 'SUB003', s.score)) 物理,
        sum(decode(s.subid,'SUB004',s.score)) 化學
     from score s
     group by s.sid) score_
 right join (select st.id, st.name, st.age, c.classname
        from student st, class c
       where c.id = st.classid) s1 on s1.id = score_.sid
 order by 總分;