MySQL面试必备训练题（常备SQL语句）

• 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 

作者：翁闻宇
链接：https://www.jianshu.com/p/4486472f2783
来源：简书
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