MySQL查询语句实操练习

题目:新建一个数据库ClassManager，包括四个表：学生表（Student）、课程表（Course）、成绩表（Score）以及教师信息表（Teacher）。四个表的结构分别如表1-1的表（一）~表（四）所示，数据如表1-2的表（一）~表（四）所示。用SQL语句创建四个表并完成相关题目。

一.表1-1数据库的表结构

表（一）Student (学生表) 

属性名	数据类型	可否为空	含 义
Sno	varchar (20)	否	学号
Sname	varchar (20)	否	学生姓名
Ssex	varchar (20)	否	学生性别
Sbirthday	datetime	可	学生出生年月
Class	varchar (20)	可	学生所在班级

表（二）Course（课程表）

属性名	数据类型	可否为空	含 义
Cno	varchar (20)	否	课程号
Cname	varchar (20)	否	课程名称
Tno	varchar (20)	否	教工编号

表（三）Score(成绩表)

属性名	数据类型	可否为空	含 义
Sno	varchar (20)	否	学号
Cno	varchar (20)	否	课程号
Degree	Decimal(4,1)	可	成绩

表（四）Teacher(教师表)

属性名	数据类型	可否为空	含 义
Tno	varchar (20)	否	教工编号
Tname	varchar (20)	否	教工姓名
Tsex	varchar (20)	否	教工性别
Tbirthday	datetime	可	教工出生年月
Prof	varchar (20)	可	职称
Depart	varchar (20)	否	教工所在部门

二.表1-2数据库中的数据

表（一）Student

Sno	Sname	Ssex	Sbirthday	class
108	曾华	男	1977-09-01	95033
105	匡明	男	1975-10-02	95031
107	王丽	女	1976-01-23	95033
101	李军	男	1976-02-20	95033
109	王芳	女	1975-02-10	95031
103	陆君	男	1974-06-03	95031

表（二）Course

Cno	Cname	Tno
3-105	计算机导论	825
3-245	操作系统	804
6-166	数字电路	856
9-888	高等数学	831

表（三）Score

Sno	Cno	Degree
103	3-245	86
105	3-245	75
109	3-245	68
103	3-105	92
105	3-105	88
109	3-105	76
101	3-105	64
107	3-105	91
108	3-105	78
101	6-166	85
107	6-166	79
108	6-166	81

表（四）Teacher

Tno	Tname	Tsex	Tbirthday	Prof	Depart
804	李诚	男	1958-12-02	副教授	计算机系
856	张旭	男	1969-03-12	讲师	电子工程系
825	王萍	女	1972-05-05	助教	计算机系
831	刘冰	女	1977-08-14	助教	电子工程系

三.完成以下操作

0.根据上述题目和表格，创建相应数据库，创建相应表结构，并插入给定数据

create database ClassManager；
use ClassManager1;

create table student (
sno varchar(20) not null comment '学号',
sname varchar(20) not null comment '学生姓名',
ssex varchar(20) not null comment '学生性别',
sbirthday datetime comment '学生出生年月',
class varchar(20) comment '学生所在班级'
);

create table course (
cno varchar(20) not null comment '课程号',
cname varchar(20) not null comment '课程名称',
tno varchar(20) not null comment '教工编号'
);

create table score (
sno varchar(20) not null comment '学号',
cno varchar(20) not null comment '课程号',
degree decimal(4,1) comment '成绩'
);

create table teacher (
tno varchar(20) not null comment '教工编号',
tname varchar(20) not null comment '教工姓名',
tsex varchar(20) not null comment '教工性别',
tbirthday datetime comment '教工出生年月',
prof varchar(20) comment '职称',
depart varchar(20) not null comment '教工所在部门'
);

insert into student (sno, sname, ssex, sbirthday, class) values ('108',    '曾华','男','1977-09-01','95033');
insert into student (sno, sname, ssex, sbirthday, class) values ('105',    '匡明','男','1975-10-02','95031');
insert into student (sno, sname, ssex, sbirthday, class) values ('107',    '王丽','女','1976-01-23','95033');
insert into student (sno, sname, ssex, sbirthday, class) values ('101',    '李军','男','1976-02-20','95033');
insert into student (sno, sname, ssex, sbirthday, class) values ('109',    '王芳','女','1975-02-10','95031');
insert into student (sno, sname, ssex, sbirthday, class) values ('103',    '陆君','男','1974-06-03','95031');

insert into course (cno, cname, tno) values ('3-105', '计算机导论',  '825');
insert into course (cno, cname, tno) values ('3-245', '操作系统',    '804');
insert into course (cno, cname, tno) values ('6-166', '数字电路',    '856');
insert into course (cno, cname, tno) values ('9-888', '高等数学',    '831');

insert into score (sno, cno, degree) values ('103', '3-245', '86');
insert into score (sno, cno, degree) values ('105', '3-245', '75');
insert into score (sno, cno, degree) values ('109', '3-245', '68');
insert into score (sno, cno, degree) values ('103', '3-105', '92');
insert into score (sno, cno, degree) values ('105', '3-105', '88');
insert into score (sno, cno, degree) values ('109', '3-105', '76');
insert into score (sno, cno, degree) values ('101', '3-105', '64');
insert into score (sno, cno, degree) values ('107', '3-105', '91');
insert into score (sno, cno, degree) values ('108', '3-105', '78');
insert into score (sno, cno, degree) values ('101', '6-166', '85');
insert into score (sno, cno, degree) values ('107', '6-166', '79');
insert into score (sno, cno, degree) values ('108', '6-166', '81');


insert into teacher (tno, tname, tsex, tbirthday, prof, depart) values ('804', '李诚','男','1958-12-02','副教授','计算机系');
insert into teacher (tno, tname, tsex, tbirthday, prof, depart) values ('856', '张旭','男','1969-03-12','讲师','电子工程系');
insert into teacher (tno, tname, tsex, tbirthday, prof, depart) values ('825', '王萍','女','1972-05-05','助教','计算机系');
insert into teacher (tno, tname, tsex, tbirthday, prof, depart) values ('831', '刘冰','女','1977-08-14','助教','电子工程系');

1. 查询Student表中的所有记录的Sname、Ssex和Class列。

select sname, ssex, class from student;

2. 查询教师所有的单位即不重复的Depart列。

select distinct depart from teacher;

3. 查询Student表的所有记录。

select * from student;

4. 查询Score表中成绩在60到80之间的所有记录。

select * from score where degree between 60 and 80;

5. 查询Score表中成绩为85，86或88的记录。

select * from score where degree in (85, 86, 88);

6. 查询Student表中“95031”班或性别为“女”的同学记录。

select * from student where class = '95031' or ssex = '女';

7. 以Class降序查询Student表的所有记录。

select * from student order by class desc;

8. 以Cno升序、Degree降序查询Score表的所有记录。

select * from score order by cno asc, degree desc;

9. 查询“95031”班的学生人数。

select count(*) from student where class = '95031';

10.查询Score表中的最高分的学生学号和课程号。

select * from score sc  where degree = (select max(degree) as max from score where cno = sc.cno group by cno);

11.查询每门课的平均成绩。

select cno, avg(degree) as avg from score group by cno;

12.查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。

select cno, avg(degree) as avg from score where cno like '3%' group by cno having count(*) >= 5;

13.查询分数大于70，小于90的Sno列。

select sno from score where degree > 70 and degree < 90;

14.查询所有学生的Sname、Cno和Degree列。

select sname, cno, degree from student s left join score sc on sc.sno = s.sno;

15.查询所有学生的Sno、Cname和Degree列。

select s.sno, c.cname, sc.degree from student s left join score sc on sc.sno = s.sno left join course c on c.cno = sc.cno;

16.查询所有学生的Sname、Cname和Degree列。

select s.sname, c.cname, sc.degree from student s left join score sc on sc.sno = s.sno left join course c on c.cno = sc.cno;

17.查询“95033”班学生的平均分。

select cno , avg(degree)  from score sc where sc.sno in (select sno from student where class = '95033') group by cno;

18.查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。

select * from score where sno = '109' and cno = '3-105';

19.查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。

select * from score where  cno = '3-105' and degree > (select degree from score where sno = '109'and cno = '3-105'); -- 此处理解为只看‘3-105’课程成绩
select * from score where degree > (select degree from score where sno = '109'and cno = '3-105'); -- 此处为各科成绩都算。

20.查询和学号为108、101的同学同年出生的所有学生的Sno、Sname和Sbirthday列。(使用year()方法对生日字段求年份)

select sno,sname,sbirthday from student where year(sbirthday) in (select year(sbirthday) from student where sno in ('108', '101'));

21.查询“张旭“教师任课的学生成绩。

select sc.* from score sc inner join course c on c.cno = sc.cno inner join teacher t on t.tno = c.tno where t.tname = '张旭'; -- 合并多个表然后查询
select * from score where cno in(select cno from course where tno in(select tno from teacher where tname ='张旭')); -- 嵌套查询

22.查询选修某课程的同学人数多于5人的教师姓名。

select tname from teacher where tno = (select tno from course where cno = (select cno from score group by cno having count(*) > 5));

23.查询95033班和95031班全体学生的记录。

select * from student where class in ('95033', '95031');

24.查询存在有85分以上成绩的课程Cno。

select distinct cno from score where degree > 85;

25.查询出“计算机系“教师所教课程的成绩表。

select * from score where cno in (select cno from course where tno in (select tno from teacher where depart = '计算机系')); 

26.查询“计算 机系”与“电子工程系“不同职称的教师的Tname和Prof。

select tname, prof from teacher where depart = '计算机系' and prof not in (select prof from teacher where depart = '电子工程系')union select tname, prof from teacher where depart = '电子工程系' and prof not in (select prof from teacher where depart = '计算机系');

27.查询所有教师和同学的name、sex和birthday。

select sname as `name`, ssex as `sex`, sbirthday as `birthday` from student union select tname, tsex,tbirthday from teacher;

28.查询所有“女”教师和“女”同学的name、sex和birthday。

select sname as `name` , ssex as `sex`, sbirthday as `birthday`from student where ssex = '女' union select tname, tsex , tbirthday from teacher where tsex = '女';

29.查询成绩比该课程平均成绩低的同学的成绩表。

select * from score sc where degree < (select avg(degree) as avg from score where cno = sc.cno group by cno);

30.查询所有任课教师的Tname和Depart。

select tname, depart from teacher where tno in (select tno from course);

31.查询所有未讲课的教师的Tname和Depart。

select tname, depart from teacher where tno in (select tno from course where cno not in (select cno from score)); -- 此处理解为没有成绩的课程为未讲课的课程。

32.查询至少有2名男生的班号。

select class from student where ssex = '男' group by class having count(*) >= 2;

33.查询Student表中不姓“王”的同学记录。

select * from student where sname not like '王%';

34.查询Student表中每个学生的姓名和年龄(使用year()方法对日期字段)。

select sname, (year(now()) - year(sbirthday)) as nian_ling from student;

35.查询Student表中最大和最小的Sbirthday日期值。

select max(sbirthday) as max,min(sbirthday) as min from student;

36.以班号和年龄从大到小的顺序查询Student表中的全部记录。

select * from student order by class desc, sbirthday asc; 

37.查询“男”教师及其所上的课程。

select t.*, c.cno, c.cname from teacher t inner join course c on c.tno = t.tno where t.tsex = '男';

38.查询最高分同学的Sno、Cno和Degree列。

select sno, cno, degree from score sc where degree = (select max(degree) as max from score where cno = sc.cno group by cno);

39.查询和“李军”同性别的所有同学的Sname。

select sname from student where ssex in (select ssex from student where sname = '李军');

40.查询和“李军”同性别并同班的同学Sname。

select sname from student where ssex in (select ssex from student where sname = '李军') and class in (select class from student where sname = '李军');

41.查询所有选修“计算机导论”课程的“男”同学的成绩表。

select * from score where cno in (select cno from course where cname = '计算机导论')and sno in (select sno from student where ssex = '男');