数据库45道题（二）
#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),Cno 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,cno,degree from student,score where student.sno = score.sno
15、查询所有学生的Sno、Cname和Degree列。
select sno,cname,degree from course,score where course.cno = score.cno
16、查询所有学生的Sname、Cname和Degree列。
select sname,cname,degree from student,course,score where student.sno=score.sno and course.cno = score.cno
17、 查询“95033”班学生的平均分。
select avg(degree) from score where sno in(select sno from student where class='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,cno,rank from score,grade where degree between low and upp
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。
select * from score where sno in(select sno from score group by sno having count(*)>1) and degree<(select max(degree) from score where sno in
(select sno from score group by sno having count(*)>1))
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'and Cno='3-105')
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 year(Sbirthday)=(select year(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 in(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 in ('95033','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 * from Teacher,Course,Score where Teacher.Depart='计算机系'and Teacher.Tno=Course.Tno and Course.Cno=Score.Cno
select * from score where cno in(select cno from course where tno in(select tno from teacher where depart='计算机系'))
28、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')
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>any(select 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>all(select 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 a where Degree<(Select Avg(Degree) from score b where cno=a.cno)
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,year(now())-year(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 course.tno=teacher.tno and 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')
