#创建表

create table Student #学生表
(
Sno varchar(20) not null primary key,
Sname varchar(20) not null,
Ssex varchar(20) not null,
Sbirthday datetime,
Class varchar(20)
);

create table Teacher #教师表
(
Tno varchar(20) not null primary key,
Tname varchar(20) not null,
Tsex varchar(20) not null,
Tbirthday datetime,
Prof varchar(20),
Depart varchar(20) not null
);

create table Course #课程表
(
Cno varchar(20) not null primary key,
Cname varchar(20) not null,
Tno varchar(20) not null,
foreign key (Tno) references Teacher(Tno)
);

create table Score #成绩表
(
ids int auto_increment primary key,
Sno varchar(20) not null,
foreign key (Sno) references Student(Sno),
Cno varchar(20) not null,
foreign key (Cno) references Course(Cno),
Degree Decimal(4,1)
);

#添加数据

#Student学生表

insert into Student values(‘108‘,‘曾华‘,‘男‘,‘1977-09-01‘,‘95033‘);

insert into Student values(‘105‘,‘匡明‘,‘男‘,‘1975-10-02‘,‘95031‘);

insert into Student values(‘107‘,‘王丽‘,‘女‘,‘1976-01-23‘,‘95033‘);

insert into Student values(‘101‘,‘李军‘,‘男‘,‘1976-02-20‘,‘95033‘);

insert into Student values(‘109‘,‘王芳‘,‘女‘,‘1975-02-10‘,‘95031‘);

insert into Student values(‘103‘,‘陆君‘,‘男‘,‘1974-06-03‘,‘95031‘);

#Teacher教师表

insert into Teacher values(‘804‘,‘李诚‘,‘男‘,‘1958-12-02‘,‘副教授‘,‘计算机系‘);

insert into Teacher values(‘856‘,‘张旭‘,‘男‘,‘1969-03-12‘,‘讲师‘,‘电子工程系‘);

insert into Teacher values(‘825‘,‘王萍‘,‘女‘,‘1972-05-05‘,‘助教‘,‘计算机系‘);

insert into Teacher values(‘831‘,‘刘冰‘,‘女‘,‘1977-08-14‘,‘助教‘,‘电子工程系‘);

#Course课程表

insert into Course values(‘3-105‘,‘计算机导论‘,‘825‘);

insert into Course values(‘3-245‘,‘操作系统‘,‘804‘);

insert into Course values(‘6-166‘,‘数字电路‘,‘856‘);

insert into Course values(‘9-888‘,‘高等数学‘,‘831‘);

#Score成绩表

insert into Score values(‘‘,‘103‘,‘3-245‘,‘86‘);

insert into Score values(‘‘,‘105‘,‘3-245‘,‘75‘);

insert into Score values(‘‘,‘109‘,‘3-245‘,‘68‘);

insert into Score values(‘‘,‘103‘,‘3-105‘,‘92‘);

insert into Score values(‘‘,‘105‘,‘3-105‘,‘88‘);

insert into Score values(‘‘,‘109‘,‘3-105‘,‘76‘);

insert into Score values(‘‘,‘101‘,‘3-105‘,‘64‘);

insert into Score values(‘‘,‘107‘,‘3-105‘,‘91‘);

insert into Score values(‘‘,‘108‘,‘3-105‘,‘78‘);

insert into Score values(‘‘,‘101‘,‘6-166‘,‘85‘);

insert into Score values(‘‘,‘107‘,‘6-166‘,‘79‘);

insert into Score values(‘‘,‘108‘,‘6-166‘,‘81‘);

#查询

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,Degree desc

9、 查询“95031”班的学生人数。

select sum(Class=95031) from Student

10、 查询Score表中的最高分的学生学号和课程号。（子查询或者排序）

select Sno,Cno from Score where degree=(select max(degree) from Score)

11、 查询每门课的平均成绩。

select avg(degree) 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 avg(degree) from Score group by Cno having count(*)>=5 and Cno like‘3%‘

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 from Student
union
select Cno from Course
union
select Degree from Score

15、查询所有学生的Sno、Cname和Degree列。

select Sno from Student
union
select Cname from Course
union
select Degree from Score

16、查询所有学生的Sname、Cname和Degree列。

select Sname from Student
union
select Cname from Course
union
select Degree from Score

17、 查询“95033”班学生的平均分。

select avg(degree) from score group by Cno=95033;

18、 假设使用如下命令建立了一个grade表：
create table grade(low int(3),upp int(3),rank char(1));
insert into grade values(90,100,‘A‘);
insert into grade values(80,89,‘B‘);
insert into grade values(70,79,‘C‘);
insert into grade values(60,69,‘D‘);
insert into grade values(0,59,‘E‘);
现查询所有同学的Sno、Cno和rank列。

select Sno from Student
union
select Cno from Course
union
select rank from grade

19、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 Cno=‘3-105‘ and Degree>(select max(Degree) from Score where Sno=‘109‘)

20、查询score中选学多门课程的同学中分数为非最高分成绩的记录。

21、 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 max(Degree) from Score where Sno=‘109‘)

22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。

select Sno,Sname,Sbirthday from Student where Sbirthday=(select Sbirthday from Student where Sno=‘108‘)

23、查询“张旭“教师任课的学生成绩。

Select degree from score where Cno=(Select Cno from course where Tno=(Select Tno from Teacher where Tname=‘张旭‘))

24、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))

25、查询95033班和95031班全体学生的记录。

Select * from Student where class="95033" or 95031

26、 查询存在有85分以上成绩的课程Cno.

Select Cno from score where degree>85

27、查询出“计算机系“教师所教课程的成绩表。

Select degree from Teacher,Course,Score where Teacher.Depart=‘计算机系‘and Teacher.Tno=Course.Tno and Course.Cno=Score.Cno

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

29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。

select Cno,Sno,Degree from Score where Cno=‘3-105‘ and Degree>(select max(degree) from Score where Cno=‘3-245‘) order by degree desc

30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.

select Cno,Sno,Degree from Score where Cno=‘3-105‘ and Degree>(select max(degree) from Score where Cno=‘3-245‘)

31、 查询所有教师和同学的name、sex和birthday.

Select Sname,Ssex,Sbirthday from Student
union
Select Tname,Tsex,Tbirthday from Teacher

32、查询所有“女”教师和“女”同学的name、sex和birthday.

Select Sname,Ssex,Sbirthday from Student where Ssex=‘女‘
union
Select Tname,Tsex,Tbirthday from Teacher where Tsex=‘女‘

33、 查询成绩比该课程平均成绩低的同学的成绩表。

Select Degree from score where Degree<(Select Avg(Degree) from score)

34、 查询所有任课教师的Tname和Depart.

select Tname,Depart from Teacher where Tno in(select Tno from Course where Cno in(select Cno from Score group by Cno))

35 、 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 group by Cno))

36、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

37、查询Student表中不姓“王”的同学记录。

select * from Student where Sname not like ‘王%‘

38、查询Student表中每个学生的姓名和年龄。

select Sname,Sbirthday from Student

39、查询Student表中最大和最小的Sbirthday日期值。

select min(Sbirthday),min(Sbirthday) from Student

40、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 Sbirthday,Class desc

41、查询“男”教师及其所上的课程。

select Cno,Tname from Course,Teacher where Tsex=‘男‘

42、查询最高分同学的Sno、Cno和Degree列。

Select Sno,Cno,Degree from Score where Degree=(select max(Degree) from Score)

43、查询和“李军”同性别的所有同学的Sname.

select Sname from Student where Ssex=(select Ssex from Student where Sname=‘李军‘)

44、查询和“李军”同性别并同班的同学Sname.

select Sname from Student where Ssex=(select Ssex from Student where Sname=‘李军‘) and class=(select Class from Student where Sname=‘李军‘)

45、查询所有选修“计算机导论”课程的“男”同学的成绩表。

select degree from score where Cno=(select Cno from Course where Cname=‘计算机导论‘) and Sno in (select sno from Student where Ssex=‘男‘)

45到数据库查询题