mysql常见查询练习题
#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
(
id 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 ); #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(1,'103','3-245','86');
insert into score values(2,'105','3-245','75');
insert into score values(3,'109','3-245','68');
insert into score values(4,'103','3-105','92');
insert into score values(5,'105','3-105','88');
insert into score values(6,'109','3-105','76');
insert into score values(7,'103','3-105','64');
insert into score values(8,'105','3-105','91');
insert into score values(9,'109','3-105','78');
insert into score values(10,'103','6-166','85');
insert into score values(11,'105','6-166','79');
insert into score values(12,'109','6-166','81');
1、 查询Student表中的所有记录的Sname、Ssex和Class列。
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select Sname,Ssex,Class from student |
2、 查询教师所有的单位即不重复的Depart列。
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select distinct Depart from teacher |
3、 查询Student表的所有记录。
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select * from student |
4、 查询Score表中成绩在60到80之间的所有记录。
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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。
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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。
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select * from Student where class='95031' or Ssex='女' |
7、 以Class降序查询Student表的所有记录。
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select * from student order by class desc |
8、 以Cno升序、Degree降序查询Score表的所有记录。
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select * from Score order by cno asc,degree desc |
9、 查询“95031”班的学生人数。
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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）
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select Sno,Cno from Score where Degree=(select max(Degree) from Score) |
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select Sno,Cno from Score order by Degree desc limit 0,1 |
11、 查询每门课的平均成绩。
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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。
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select avg(Degree) from score where Cno like '3%' and Cno in (select Cno from score group by Cno having count(*)>=5) 用in 不用= 是因为可能会有多个 |
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简单写法：select avg(Degree) from score where Cno like '3%' and group by Cno having count(*)>=5 |
13、 查询分数大于70，小于90的Sno列。
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select Sno from Score where degree>70 and degree<90 |
14、 查询所有学生的Sname、Cno和Degree列。
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select Sname, Cno,Degree from Score , student where Score.Sno=student.Sno |
15、 查询所有学生的Sno、Cname和Degree列。
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select Sno,Cname,Degree from Score , Course where Score.Cno=Course.Cno |
16、 查询所有学生的Sname、Cname和Degree列。
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select Sname,Cname,Degree from student,course,score where student.Sno=score.Sno and course.Cno=score.Cno |
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join .. on 写法：select Sname,Cname,Degree from student join score on student.Sno=score.Sno join course on course.Cno=score.Cno |
17、 查询“95033”班学生的平均分。
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select avg(degree) as 'class=95033' 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。
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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。
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<span style="color: #000000; font-size: 15px">109同学，选修是3-105课的</span> |
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select * from score where Cno='3-105' and degree>(select max(degree ) from Score where Sno='109' and Cno='3-105' ) |
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<span style="font-size: 15px">109同学，没有选修3-105课</span> |
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select * from score where Cno='3-105' and degree>(select max(degree ) from Score where Sno='109') |
and degree<( select max(degree ) from Score where sno in (select Sno from score group by Sno having count(*)>1))
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选了多门课程并且是这个课程下不是最高分的 |
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select * from score a where Sno in (select Sno from score group by Sno having count(*)>1) and degree<( select max(degree ) from Score b where b.cno = a.cno) |
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。
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Select * from score where degree>(select degree from Score where Sno='109' and Cno='3-105' ) |
22、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。
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select sno,sname,sbirthday from student where year(sbirthday) = (select year(sbirthday) from student where sno='108') |
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select sno,sname,sbirthday from student where year(sbirthday) = (select year(sbirthday) from student where sno='101') |
23、查询“张旭“教师任课的学生成绩。
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select Sno,degree from score,Course where score.Cno=Course.Cno and Course.Tno= (select Tno from Teacher where Tname='张旭' ) |
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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。
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select Tname from Teacher, Course where Teacher.Tno=Course.Tno and Course.Cno =(select Cno from Score group by Cno having count(*)>5) |
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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。
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select * from student where class in ('95033','95031') |
26、 查询存在有85分以上成绩的课程Cno.
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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。
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select * from course 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。
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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')<br>union <br>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。
any:代表括号中任意一个成绩就可以
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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.
all:代表括号中的所有成绩
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select Cno,Sno,Degree from score where cno='3-105' and degree >all(select degree from score where cno='3-245' ) order by degree desc |
31、 查询所有教师和同学的name、sex和birthday.
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select tname,tsex,tbirthday from Teacher union select sname,ssex,sbirthday from Student |
32、查询所有“女”教师和“女”同学的name、sex和birthday.
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select Tname,Tsex,Tbirthday from Teacher where Tsex='女' union select Sname,Ssex,Sbirthday from Student where Ssex='女' |
33、 查询成绩比该课程平均成绩低的同学的成绩表。
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select * from score a where degree < (select avg(degree) from score b where b.cno=a.cno) |
34、 查询所有任课教师的Tname和Depart.
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select Tname,Depart from Teacher where tno in (select tno from course ) |
35 、 查询所有未讲课的教师的Tname和Depart.
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select Tname,Depart from Teacher where Tno not in (select Tno from Course where cno in (select cno from score )) |
36、查询至少有2名男生的班号。
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select class from student where ssex='男' group by class having count(*)>1 |
37、查询Student表中不姓“王”的同学记录。
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select * from Student where Sname not like '王%%' |
38、查询Student表中每个学生的姓名和年龄。
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select Sname, year(now())-year(sbirthday) from Student |
39、查询Student表中最大和最小的Sbirthday日期值。
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select Max(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。
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select * from Student order by class desc, Sbirthday |
41、查询“男”教师及其所上的课程。
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select Tname,Cname from course,teacher where course.tno= teacher.tno and teacher.Tsex='男' |
42、查询最高分同学的Sno、Cno和Degree列。
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select Sno,Cno,Degree from score where degree=(select max(degree) from score) |
排序写法：
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select Sno,Cno,Degree from score order by degree desc limit 0,1 |
43、查询和“李军”同性别的所有同学的Sname.
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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.
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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。
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select Sno,Cno,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') |
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