MySQL经典试题(45道)
MySql 语句练习45题
创建四张表 分别存储 学生信息 课程信息 分数 讲师信息表 存储相应数据
建立表结构
学生信息表 Student
字段名 字段类型 字段约束 / 含义
Sno Varchar(3) Not null / 学员编号
Sname Varchar(4) Not null / 学员姓名
Ssex Varchar(2) Not null / 性别
Sbirthday Datetime 生日
Classnum Varchar(5) 班级号
CREATE TABLE STUDENT(
SNO VARCHAR(3) NOT NULL,
SNAME VARCHAR(4) NOT NULL,
SSEX VARCHAR(2) NOT NULL,
SBIRTHDAY DATETIME,
CLASS VARCHAR(5));
课程信息表 course
字段名 字段类型 字段约束 / 含义
Cno Varchar(5) Not null / 课程编号
Cname Varchar(10) Not null / 课程名称
Tno Varchar(10) Not null / 授课老师编号
CREATE TABLE COURSE
(CNO VARCHAR(5) NOT NULL,
CNAME VARCHAR(10) NOT NULL,
TNO VARCHAR(10) NOT NULL);
成绩表 score
字段名 字段类型 字段约束 / 含义
Sno Varchar(3) Not null / 学员编号
Cno Varchar(5) Not null / 课程编号
Degree Double(3,1) Not null / 分数
CREATE TABLE SCORE
(SNO VARCHAR(3) NOT NULL,
CNO VARCHAR(5) NOT NULL,
DEGREE NUMERIC(10, 1) NOT NULL);
讲师表 teacher
字段名 字段类型 字段约束 / 含义
Tno Varchar(3) Not null / 讲师编号
Tname Varchar(4) Not null / 讲师姓名
Tsex Varchar(2) Not null / 讲师性别
Tbirthday Datetime Not null / 出生日期
Prof Varchar(6) 等级
Depart Varchar(10) 所属院系
CREATE TABLE TEACHER
(TNO VARCHAR(3) NOT NULL,
TNAME VARCHAR(4) NOT NULL, TSEX VARCHAR(2) NOT NULL,
TBIRTHDAY DATETIME NOT NULL, PROF VARCHAR(6),
DEPART VARCHAR(10) NOT NULL);
向表中插入数据
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (108 ,'曾华' ,'男' ,"1977-09-01",95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (105 ,'匡明' ,'男' ,"1975-10-02",95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (107 ,'王丽' ,'女' ,"1976-01-23",95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (101 ,'李军' ,'男' ,"1976-02-20",95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (109 ,'王芳' ,'女' ,"1975-02-10",95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (103 ,'陆君' ,'男' ,"1974-06-03",95031);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-105' ,'计算机导论',825);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-245' ,'操作系统' ,804);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('6-166' ,'数据电路' ,856);
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('9-888' ,'高等数学' ,100);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (103,'3-245',86);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (105,'3-245',75);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (109,'3-245',68);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (103,'3-105',92);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (105,'3-105',88);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (109,'3-105',76);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (101,'3-105',64);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (107,'3-105',91);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'3-105',78);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (101,'6-166',85);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (107,'6-106',79);
INSERT INTO SCORE(SNO,CNO,DEGREE)VALUES (108,'6-166',81);
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (804,'李诚','男','1958-12-02','副教授','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (856,'张旭','男','1969-03-12','讲师','电子工程系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (825,'王萍','女','1972-05-05','助教','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (831,'刘冰','女','1977-08-14','助教','电子工程系');
练习题及SQL
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 SNO,SNAME,SSEX,SBIRTHDAY,CLASS
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 ssex = '女' or class = 95031;
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(*) '人数'
from student
where class = 95031;
10、查询Score表中的最高分的学生学号和课程号。
# 1
select sno,cno from score where degree = (select max(degree) from score);
# 2
select sno,cno from score order by degree desc limit 1;
11、查询‘3-105’号课程的平均分。
select avg(degree) '3-105号课程的平均分'
from score
where cno = '3-105'
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 sno,cno,avg(degree)
from score
group by cno
having cno like'3%' and count(cno)>=5;
13、查询最低分大于70,最高分小于90的Sno列。
select sno
from score
group by sno
having min(degree)>70 and max(degree)<90
14、查询所有学生的Sname、Cno和Degree列。
select sname,cno,degree
from student
join score
on student.sno= score.sno
15、查询所有学生的Sno、Cname和Degree列。
select student.sno,sname,degree
from student
join score on student.sno= score.sno
16、查询所有学生的Sname、Cname和Degree列。
select sname,sname,degree
from student
join score on student.sno= score.sno
17、查询“95033”班所选课程的平均分。
select avg(degree) from student
join score on student.sno= score.sno
where student.class = '95033'
18、假设使用如下命令建立了一个grade表,现查询所有同学的Sno、Cno和rank列
create table grade(low number(3,0),upp number(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’);
commit;
select sno,cno,rank from score
join grade on 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 student
where sno in(
select sno
from score
where cno='3-105' and degree>(
select degree
from score
where cno='3-105'and sno='109'
)
)
20、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。
select *from score a
where sno in(
# 查找出一门以上课程的学生的学号
select sno from score group by sno having COUNT(*)>1
)
and degree not in(
# 找出每个科目的最高分
select MAX(degree) from score b where a.cno=b.cno group by 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。
select *
from score
where degree>(
select degree
from score
where cno='3-105'and sno='109'
)
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) in (
select year(sbirthday)
from student
where sno = '108'
)
23、查询“张旭“教师任课的学生成绩。
# 1
select *from score
join course on course.cno=score.cno
join teacher on course.tno=teacher.tno
where teacher.tname='张旭'
# 2
select *
from score
where cno = (select cno
from course
where course.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 teacher.tname
from teacher
join course on teacher.tno = course.tno
where course.cno in (
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 = '95033' or class='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 score
where cno in(
select cno
from course
where tno in(
select teacher.tno
from teacher
where teacher.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。
# 李诚
select tname,prof
from teacher
# 副教授、助教
where depart ='计算机系' and prof not in(
# 讲师、助教
select prof
from teacher
where depart ='电子工程系'
)
union
# 讲师
select tname,prof
from teacher
# 讲师、助教
where depart ='电子工程系' and prof not in(
# 副教授、助教
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 *
from score
where cno='3-105' and degree>(
select min(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
# all关键字相当于and,如果all()括号里面返回的是data[2]
# 那么这段SQL就相当于degree>data[0] and degree>data[1]
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 as birthday
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 as birthday
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 *
from score a
where degree<(
select avg(degree)
from score b
where a.cno=b.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
);
35、查询所有未讲课的教师的Tname和Depart.
select tname,depart
from teacher
where tno not in(
select tno
from course
);
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,2020-year(sbirthday) as age
from student
39、查询Student表中最大和最小的Sbirthday日期值。
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。
select 2020-year(sbirthday) as age,class
from student
order by class desc,age desc
41、查询“男”教师及其所上的课程。
select tname,cname
from teacher
join course
on teacher.tno = course.tno
where 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 *
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 s.*
from student s,(
select ssex,class from student where sname = '李军'
)as a
where s.ssex = a.ssex and s.class = a.class
45、查询所有选修“计算机导论”课程的“男”同学的成绩表
# 1.
select score.*
from student join score on student.sno = score.sno
join course on score.cno = course.cno
where course.cname = '计算机导论' and student.ssex = '男'
# 2.
select *
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'
);