oracle 数据库 50道经典例题

/*
表结构：
--1.学生表
Student(S#,Sname,Sage,Ssex) --S# 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别
--2.课程表
Course(C#,Cname,T#) --C# --课程编号,Cname 课程名称,T# 教师编号
--3.教师表
Teacher(T#,Tname) --T# 教师编号,Tname 教师姓名
--4.成绩表
SC(S#,C#,score) --S# 学生编号,C# 课程编号,score 分数


select * from Student
select * from Course
select * from Teacher
select * from SC
*/
--准备工作：建表、新增测试数据
create table Student(S# varchar2(10),Sname varchar2(10),Sage date,Ssex varchar2(10));
insert into Student values('01' , '赵雷' , to_date('1990-01-01','yyyy-mm-dd') , '男');
insert into Student values('02' , '钱电' , to_date('1990-12-21','yyyy-mm-dd') , '男');
insert into Student values('03' , '孙风' , to_date('1990-05-20','yyyy-mm-dd') , '男');
insert into Student values('04' , '李云' , to_date('1990-08-06','yyyy-mm-dd') , '男');
insert into Student values('05' , '周梅' , to_date('1991-12-01','yyyy-mm-dd') , '女');
insert into Student values('06' , '吴兰' , to_date('1992-03-01','yyyy-mm-dd') , '女');
insert into Student values('07' , '郑竹' , to_date('1989-07-01','yyyy-mm-dd') , '女');
insert into Student values('08' , '王菊' , to_date('1990-01-20','yyyy-mm-dd') , '女');


create table Course(C# varchar2(10),Cname varchar2(10),T# varchar2(10));
insert into Course values('01' , '语文' , '02');
insert into Course values('02' , '数学' , '01');
insert into Course values('03' , '英语' , '03');


create table Teacher(T# varchar2(10),Tname varchar2(10));
insert into Teacher values('01' , '张三');
insert into Teacher values('02' , '李四');
insert into Teacher values('03' , '王五');


create table SC(S# varchar2(10),C# varchar2(10),score number(4,1));
insert into SC values('01' , '01' , 80);
insert into SC values('01' , '02' , 90);
insert into SC values('01' , '03' , 99);
insert into SC values('02' , '01' , 70);
insert into SC values('02' , '02' , 60);
insert into SC values('02' , '03' , 80);
insert into SC values('03' , '01' , 80);
insert into SC values('03' , '02' , 80);
insert into SC values('03' , '03' , 80);
insert into SC values('04' , '01' , 50);
insert into SC values('04' , '02' , 30);
insert into SC values('04' , '03' , 20);
insert into SC values('05' , '01' , 76);
insert into SC values('05' , '02' , 87);
insert into SC values('06' , '01' , 31);
insert into SC values('06' , '03' , 34);
insert into SC values('07' , '02' , 89);
insert into SC values('07' , '03' , 98);


--习题go


--1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数
--方法1
select s.*,s1.sc1 "01课程成绩",s2.sc2 "02课程成绩"
from Student s,
(select  sc.s# s#1,sc.score sc1 from Student s,SC sc where s.s#=sc.s# and sc.c#='01') s1,
(select sc.s# s#2,sc.score sc2 from Student s,SC sc where s.s#=sc.s# and sc.c#='02') s2
where s.s#=s1.s#1 and s.s#=s2.s#2 and s1.sc1>s2.sc2;