实操题1

建表准备

#建学生信息表student

create table student
(
sno varchar(20) not null primary key,

sname varchar(20) not null,

ssex varchar(20) not null,

sbirthday datetime,

class varchar(20)
);

#建立教师表

create table teacher
(
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
);

#建立课程表course

create table course
(
cno varchar(20) not null primary key,

cname varchar(20) not null,

tno varchar(20) not null,

foreign key(tno) references teacher(tno)
);

#建立成绩表

CREATE TABLE score (
sno VARCHAR (20) NOT NULL ,

FOREIGN KEY (sno) REFERENCES student (sno),

cno VARCHAR (20) NOT NULL,

FOREIGN KEY (cno) REFERENCES course (cno),

degree DECIMAL
);

数据录入

#添加学生信息

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');

#添加教师表

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');

#添加课程表

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');

#添加成绩表

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('103','3-105','64');
insert into score values('105','3-105','91');
insert into score values('109','3-105','78');
insert into score values('103','6-166','85');
insert into score values('105','6-166','79');
insert into score values('109','6-166','81');

题目：

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>=60 and degree <=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 and 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。（子查询或者排序）

select sno,cno from score order by degree desc limit 1
select sno,cno from score where degree = (select max(degree) from score)

12. 查询每门课的平均成绩

select co.cno,co.cname,avg(sc.degree) from course as co INNER JOIN score as sc on
sc.cno=co.cno group by co.cno

13. 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) from score GROUP BY cno HAVING count(*)>5 and cno LIKE '3%’ 

14. 查询分数大于70，小于90的Sno列

select sno,cno from score where degree>70 and degree<90

15. 查询所有学生的Sname、Cno和Degree列

select st.sname,co.cno,sc.degree from student as st INNER JOIN score as sc on sc.sno=st.sno
INNER JOIN course as co ON co.cno=sc.cno

16. 查询所有学生的Sno、Cname和Degree列

select st.sno,co.cname,sc.degree from student as st INNER JOIN score as sc on sc.sno=st.sno
INNER JOIN course as co ON co.cno=sc.cno

17. 查询“95031”班学生的平均分

select avg(sc.degree) from student as st INNER JOIN score as sc ON st.sno=sc.sno where class=95031

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 student as st INNER JOIN score as sc ON sc.sno=st.sno where sc.cno='3-105'

and

sc.degree>(select max(degree) 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 student as st INNER JOIN score as sc ON sc.sno=st.sno where
sc.degree>(select max(degree) from score where sno=109 and cno='3-105')