SQL 实验详细源码参考

-- ----------------------------------------------------------------------------------
-- 数据库初始化 （实验二 数据描述、定义实验）
-- ----------------------------------------------------------------------------------
create  database s_13420228;
use s_13420228;

create table student(
    sno varchar(8),
    sname varchar(20) not null,  -- 姓名
    sage smallint,  -- 年龄
    ssex char(8),  -- 性别
    sdept varchar(20) ,  -- 所在系
    constraint s_pk primary key (sno),  -- 主码
    constraint s1 check(sage between 16 and 40),
    constraint s2 check(ssex in('male','female')),
    constraint s3 check(grade between 0 and 100)
 );

create table course(
    cno varchar(7),  -- 课程号
    cname varchar(50),  -- 课程名
    cpno varchar(50),  -- 先行课
    ccredit numeric(2,1),  -- 学分,精确存储3.5
    constraint c_pk primary key (cno,cname),  -- 主码
    constraint s4 foreign key (cpno) references course (cno)  -- 先行课必须要存在
);

create table sc(  -- 学生选课表
    sno varchar(8),  -- 学号
    cno varchar(7),  -- 课程号
    grade smallint,  -- 成绩
    constraint sc_pk primary key (sno,cno),  -- 主码
    constraint s5 foreign key (sno) references student(sno) on delete cascade on update cascade,  -- sc中的学号必须存在,级联删除、更新
    constraint s6 foreign key (cno) references course(cno) on delete cascade on update cascade -- sc中课程号必须存在
);

insert into course values('01', 'Database', null, 4.0);  -- 插入数据 course
insert into course values('02', 'Operating System', null, 3.5);
insert into course values('03', 'Computer Networking', null, 4.0);
insert into course values('04', 'Data Structures', null, 4.0);
insert into course values('05', 'The C++ Programming Language', null, 4.0);
insert into course values('06', 'The C Programming Language', null, 4.0);
insert into course values('07', 'Physical Principles', null, 2.0);
insert into course values('08', 'Music Video Production', null, 3.0);
insert into course values('09', 'Computational Biology', null, 3.0);
insert into course values('10', 'Genetics', null, 3.0); --  Biology
insert into course values('11', 'Intro. to Biology', null, 3.0);

insert into student values('13420201', 'Zhang', 18,'male', 'CS');  -- 插入数据 student
insert into student values('13420202', 'Shankar', 20,'male', 'CS');
insert into student values('13420203', 'Brandt', 18,'male', 'CS');
insert into student values('13420204', 'Chavez', 19,'female', 'CS');
insert into student values('13312205', 'Peltier', 21,'female', 'Music');
insert into student values('13312213', 'Levy', 20,'female', 'Music');
insert into student values('13312137', 'Williams',20, 'male', 'Music');
insert into student values('13523111', 'Bourikas', 19,'male', 'Biology');
insert into student values('13523222', 'Smith', 19,'male', 'Biology');
insert into student values('13453334', 'Snow', 19,'male', 'Physics');

insert into sc values('13420201', '01', 80);  -- 插入数据 sc  CS
insert into sc values('13420201', '02', 70);
insert into sc values('13420201', '03', 90);
insert into sc values('13420201', '04', 40);
insert into sc values('13420201', '05', 60);
insert into sc values('13420201', '06', 90);

insert into sc values('13420202', '01', 80);
insert into sc values('13420202', '03', 90);
insert into sc values('13420202', '04', 30);
insert into sc values('13420202', '05', 70);
insert into sc values('13420202', '06', 90);

insert into sc values('13420203', '01', 80);
insert into sc values('13420203', '02', 90);
insert into sc values('13420203', '03', 90);
insert into sc values('13420203', '04', 85);
insert into sc values('13420203', '05', 75);
insert into sc values('13420203', '06', 90);

insert into sc values('13420204', '01', 55);
insert into sc values('13420204', '02', 55);
insert into sc values('13420204', '03', 90);
insert into sc values('13420204', '04', 55);
insert into sc values('13420204', '05', 70);
insert into sc values('13420204', '06', 90);

insert into sc values('13312205', '08', 90);  -- Music
insert into sc values('13312213', '08', 60);
insert into sc values('13312137', '08', 60);

insert into sc values('13523111', '09', 60);  -- Biology
insert into sc values('13523111', '10', 59);
insert into sc values('13523111', '11', 80);

insert into sc values('13453334', '07', 70);  -- Physics

update course set cpno = '04' where cno = '01';  -- 更新 course
update course set cpno = '04' where cno = '02';
update course set cpno = '05' where cno = '03';
update course set cpno = '05' where cno = '04';
update course set cpno = '06' where cno = '05';

-- --------------------初始化完成----------------------------------------------------------

-- 建立索引可以加快查询速度
create index grade_index on sc(grade);  -- 多值索引
create unique index sno_index on student(sno);  -- 唯一索引，每一个索引值只对应一个唯一的数据记录
drop index grade_index on sc;  -- 删除索引
drop index sno_index on student;

alter table student add birthday date;  -- 添加属性列
alter table student drop sage;  -- 删除属性列

alter table course drop foreign key s3;  -- 删除约束s3
alter table course add constraint s3 foreign key (cpno) references course (cno)
on delete cascade on update cascade; -- 先行课必须要存在,添加级联删除、更新

delete from course where cno = '04';  -- 删除特定元组

delete from student;  -- 删除关系student的所有元组
delete from sc;
delete from course;
drop table student;  -- 完全删除student，包括student这个模式及其所有元组
drop table sc;
drop table course;

-- ----------------------------------------------------------------------------------
-- (实验三 数据更新实验)
-- ----------------------------------------------------------------------------------

-- 插入某个学生的选课信息(外码约束，拒绝的)
insert into sc values('13436214','01',0);

-- 求各系学生的平均成绩，并把结果存入数据库
create table sdept_avg_grade (
    sdept varchar(20),
    avg_grade smallint,
    constraint sag_pk primary key (sdept),
    constraint s7 check(avg_grade between 0 and 100)
    -- constraint s8 foreign key (sdept) references student(sdept)  -- 由于外码属性必须为莫关系的主码，此外码定义语句错误
);

insert into sdept_avg_grade
select sdept,avg(grade) from sc,student where sc.sno = student.sno group by sdept ;

drop tables sdept_avg_grade;

--   将“CS”系全体学生的成绩置零
update sc set grade = 0 where 'CS' = (
select sdept from student where sc.sno = student.sno);

-- 删除“CS”系全体学生的选课记录
delete from sc where 'CS' = (
select sdept from student where sc.sno = student.sno);

-- 删除学号为“13420201”的相关信息(级联删除cascade)
delete from student where sno = '13420201';

--  将学号为“13420202”的学生的学号修改为“12420202”（级联更新）
update student set sno = '12420202' where sno = '13420202';

-- 把平均成绩大于80分的男同学的学号和平均成绩存入另一个表S_GRADE（SNO，AVG_GRADE）
create table s_grade(
    sno varchar(8),
    avg_grade smallint,
    constraint sg_pk primary key (sno),
    constraint s9 foreign key (sno) references student(sno),
    constraint s10 check(grade between 0 and 100)
);
insert into s_grade
select sc.sno,avg(grade) from sc,student where sc.sno = student.sno and ssex = 'male'
group by sc.sno having avg(grade) > 80;

select * from s_grade;
drop table s_grade;

-- 把选修了课程名为“Data Structures”的学生的成绩提高10%；
update sc set grade = grade * 1.1 where 'Data Structures' = (
select cname from course where sc.cno = course.cno );

select sno,grade from sc,course where sc.cno = course.cno and cname = 'Data Structures';
select avg(grade) from sc,course where sc.cno = course.cno and  cname = 'Data Structures';


-- ---------------------------------------------------------------------------------------------
-- (实验四 数据查询实验)
-- ---------------------------------------------------------------------------------------------

-- 1．   查询学生的基本信息；
select * from student;

-- 2．   查询“CS”系学生的基本信息
select * from student where sdept = 'CS';

-- 3．   查询“CS”系学生年龄不在19到21之间的学生的学号、姓名；
select sno,sname from student where sdept = 'CS' and sage not between 19 and 21;

-- 4．   找出最大年龄；
select max(sage) from student;

-- 5．   找出“CS”系年龄最大的学生，显示其学号、姓名；
select sno,sname from student where sdept = 'CS' and sage = (
select max(sage) from student where sdept = 'CS');

-- 6．   找出各系年龄最大的学生，显示其学号、姓名；
select sno,sname from student as s1 where sage = (
select max(sage) from student as s2 where s1.sdept = s2.sdept);

-- 7．   统计“CS”系学生的人数；
select count(sno) as number_of_student from student where sdept = 'CS';

-- 8．   统计各系学生的人数，结果按升序排列；
select sdept, count(sno) as number_of_student from student group by sdept order by number_of_student;

-- 9．   按系统计各系学生的平均年龄，结果按降序排列；
select sdept,avg(sage) as avg_age from student group by sdept order by avg_age desc;

-- 10．  查询每门课程的课程名；
select cname from course;

-- 11．  查询无先修课的课程的课程名和学分数；注意空值测试语句 'is null' or 'is not null';
select cname,ccredit from course where cpno is null;

-- 12．  统计无先修课的课程的学分总数；
select sum(ccredit) as total_credit from course where cpno is null;

-- 13．  统计每位学生选修课程的门数、学分及其平均成绩；
select sc.sno, count(sc.sno) as number_of_course, sum(ccredit) as number_of_credit, avg(grade) as avg_grade
from sc, course where sc.cno = course.cno group by sc.sno;

-- 14．  统计选修每门课程的学生人数及各门课程的平均成绩；
select cno,count(sno) as number_of_student, avg(grade) as avg_grade from sc group by cno;

-- 15．  找出平均成绩在85分以上的学生，结果按系分组，并按平均成绩的升序排列；
select sc.sno, avg(grade) as avg_grade from sc,student where sc.sno = student.sno
group by sc.sno, sdept having avg_grade >= 85 order by avg_grade;

-- 16．  查询选修了“01”或“02”号课程的学生学号和姓名；
select  distinct sc.sno,sname from sc,student where sc.sno = student.sno and (cno = '01' or cno = '02');

-- 17．  查询选修了“1”和“2”号课程的学生学号和姓名；
select distinct s1.sno,sname from sc as s1,student where s1.sno = student.sno and cno = '01' and '02' in (
select cno from sc as s2 where s2.sno = s1.sno);

select distinct sc.sno,sname from sc,student where sc.sno = student.sno and cno = '01' and sc.sno in (
select sno from sc where cno = '02');

-- 18．  查询选修了课程名为“Database”且成绩在60分以下的学生的学号、姓名和成绩；
select sc.sno,sname,grade from sc,student,course where student.sno = sc.sno and sc.cno = course.cno
and cname = 'Database' and grade < 60;

-- 19．  查询每位学生选修了课程的学生信息（显示：学号，姓名，课程号，课程名，成绩）；
select sc.sno,sname,sc.cno,cname,grade from sc,student,course where student.sno = sc.sno
and sc.cno = course.cno;

-- 20．  查询没有选修课程的学生的基本信息；
select sno,sname,sage,ssex,sdept from student where sno not in (select sno from sc);

-- 21．  查询选修了3门以上课程的学生学号；
select sno from sc group by sno having count(sno) >= 3;

-- 22．  查询选修课程成绩至少有一门在80分以上的学生学号；
select sno from sc group by sno having max(grade) > 80;

-- 23．  查询选修课程成绩均在80分以上的学生学号；
select sno from sc group by sno having min(grade) > 80;

-- 24．  查询选修课程平均成绩在80分以上的学生学号；
select sno from sc group by sno having avg(grade) > 80;

-- -----------------------------------------------------
drop database s_13420228;