MySQL面试必备训练题（常备SQL语句）

作者: f050d162bcc1 | 来源:发表于2019-01-27 23:52 被阅读85次

student表

student表

course表

course表

score表

score表

teacher表

teacher表

#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 ,
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

);

#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');

1、查询Student表中的所有记录的Sname、Ssex和Class列。

select Sname,Ssex,Class from Student;

01

2、查询教师所有的单位即不重复的Depart列。

select distinct Depart from Teacher

02

3、查询Student表的所有记录。

select * from Student

03

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;

04

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);

05

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';

06

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;

08

9、查询“95031”班的学生人数。

select COUNT(*) from Student where Class=95031;

09

10、查询Score表中的最高分的学生学号和课程号。

select Sno,Cno from Score where Degree=(select MAX(Degree) from Score);

10

11、查询每门课的平均成绩。

 SELECT cno,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 cno,AVG(degree) FROM score GROUP BY cno HAVING COUNT(cno) > 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--分数大于70，小于90的Sno列

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。

15

16、查询所有学生的Sname、Cname和Degree列。

select Sname,Cname,Degree from student join Score on Student.Sno=Score.Sno join Course on Score.Cno=Course.Cno

17、查询“95031”班学生的平均分。

select AVG(degree)from Student join Score on Student.Sno=Score.Sno and Class='95031'

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。

18

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 degree from score where Sno='109' and Cno='3-105')

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。

20

21、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 in (select Tno from Teacher where Tname = '张旭')) 

select degree from Score join Course on Score.Cno=Course.Cno join Teacher on Course.Tno=Teacher.Tno where Tname = '张旭'

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(Cno)>=5))

23、查询95033班和95031班全体学生的记录。

select*from student inner join Score on Student.Sno=Score.Sno where Class in(95033,95031)

select *from Student,Score where Class in(95033,95031) and Student.Sno=Score.Sno

24、查询存在有85分以上成绩的课程Cno.

select distinct Cno from Score where degree>=85;--去重

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'))

select Sno,Score.Cno,Degree from Score join Course on Score.Cno=Course.Cno join Teacher on Course.Tno=Teacher.Tno 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 Prof not in
(select prof from Teacher where Depart='电子工程系' and Prof in (select Prof from Teacher where Depart='计算机系'))
and Depart in ('计算机系','电子工程系')

--查询两个系中教师相同职称名称，不在这里面的就是除去两个系都有的剩下的，见上面
select prof from Teacher where Depart='电子工程系' and Prof in (select Prof from Teacher where Depart='计算机系')

27、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 a where (select Degree from Score b where Cno='3-105' and b.Sno=a.Sno)>=(select Degree from Score c where Cno='3-245' and c.Sno=a.Sno) order by Degree desc

28、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 a where (select Degree from Score b where Cno='3-105' and b.Sno=a.Sno)>(select Degree from Score c where Cno='3-245' and c.Sno=a.Sno)

29、查询所有教师和同学的name、sex和birthday.--表连接，union（纵向连接，表1和表2数据类型要对应且列数对应）上下链接，与join on左右相关链接不同

select distinct Sname as name,Ssex as sex,Sbirthday as birthday from student
union
select distinct Tname as name,Tsex as sex,Tbirthady as birthday from Teacher

30.查询所有“女”教师和“女”同学的name、sex和birthday.

select distinct Sname as name,Ssex as sex,Sbirthday as birthday from student where Ssex='女'
union
select distinct Tname as name,Tsex as sex,Tbirthady as birthday from Teacher where Tsex='女'

31.查询成绩比该课程平均成绩低的同学的成绩表。--相关子查询--同一门学科的平均分,，每门学科低于自身平均分的

select Sno,Cno,Degree from Score a where a.Degree<(select AVG(Degree) from Score b where a.Cno=b.Cno)

32.查询所有任课教师的Tname和Depart.

select Tname,Depart from Teacher where Tname in (select distinct Tname from Teacher,Course,Score where Teacher.Tno=Course.Tno and Course.Cno=Score.Cno)


select Tname,Depart from Teacher where tno in (select tno from course where Cno in (select distinct Cno from Score))

33.查询所有未讲课的教师的Tname和Depart.

select Tname,Depart from Teacher where Tname not in (select distinct Tname from Teacher,Course,Score where Teacher.Tno=Course.Tno and Course.Cno=Score.Cno)

34.查询至少有2名男生的班号。

select Class FROM student where Ssex='男' group by Class having COUNT(*)>1

35.查询Student表中不姓“王”的同学记录。

select * from student where Sname not like ('王%')

36、查询Student表中每个学生的姓名和年龄。

select Sname,YEAR(GETDATE())-year(Sbirthday) from student

37、查询Student表中最大和最小的Sbirthday日期值。

select MAX(Sbirthday) as 最大,MIN(Sbirthday) as 最小 from student

38、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

39、查询“男”教师及其所上的课程。

select Tname,Cname from Teacher,Course where Tsex='男' and Teacher.Tno=Course.Tno

40、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)

41、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') and Sname not in ('李军')

42、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 Sname not in ('李军') and Class=(select Class from student where Sname='李军')

43、查询所有选修“计算机导论”课程的“男”同学的成绩表。

select Sno,Degree from Score where Sno in (select Sno from student where Ssex='男') and Cno in (select Cno from Course where Cname='计算机导论')

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