MySQL查询练习（适合mysql查询基础弱的同学，含答案）

1. 建表语句

#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

);

2. 插入数据

#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');

3. 查询练习

# 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 degree FROM score WHERE degree >= 60 and degree <= 80;
SELECT degree 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 degree 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" or 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, Degree DESC;

# 9、查询“95031”班的学生人数

SELECT COUNT(sno) 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,degree FROM score WHERE degree = (SELECT MAX(degree) FROM score)

# 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 WHERE cno LIKE '3%' and cno in (SELECT cno FROM score GROUP BY cno HAVING COUNT(sno) >= 5);

# 13、查询分数大于70，小于90的Sno列。

SELECT * FROM score WHERE degree BETWEEN 70 AND 90;

# 14、查询所有学生的Sname、Cno和Degree列。

SELECT s.sname,sc.cno,sc.degree FROM student s LEFT JOIN score sc on s.sno = sc.sno;

# 15、查询所有学生的Sno、Cname和Degree列。

SELECT s.sno,c.cname,sc.degree FROM student s INNER JOIN score sc on s.sno = sc.sno INNER JOIN course c on c.cno = sc.cno;

# 16、查询所有学生的Sname、Cname和Degree列。

SELECT s.sname,c.cname,sc.degree FROM student s INNER JOIN score sc on s.sno = sc.sno INNER JOIN course c on c.cno = sc.cno;

# 17、查询“95033”班学生的平均分。

SELECT AVG(sc.degree) FROM student s INNER JOIN score sc on s.sno = sc.sno WHERE s.class = "95033"
SELECT AVG(sc.degree) FROM score sc WHERE sc.sno in (SELECT s.sno FROM student s WHERE s.class = "95033");

# 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 sno,degree FROM score WHERE cno = "3-105" and degree > (SELECT max(sc.degree) FROM score sc WHERE sc.sno = "109" and sc.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。

SELECT Sno, Sname, Sbirthday FROM student WHERE YEAR(Sbirthday) in (SELECT YEAR(sbirthday) FROM student WHERE sno in ("108", "101"));

# 21、查询“张旭“教师任课的学生成绩。

SELECT sno, degree FROM score WHERE cno in (SELECT cno FROM course WHERE tno in (SELECT tno FROM teacher 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 teacher.tname FROM course LEFT JOIN teacher on teacher.tno = course.tno WHERE cno in (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 where class in ("95033", "95031");

# 24、查询存在有85分以上成绩的课程Cno.

SELECT cno FROM score where degree > 85;

# 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"));

# 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 in (SELECT Prof FROM teacher WHERE depart = "计算机系") and prof not in (SELECT Prof FROM teacher WHERE depart = "电子工程系")) 
OR (Prof not in (SELECT Prof FROM teacher WHERE depart = "计算机系") and prof in (SELECT Prof FROM teacher WHERE depart = "电子工程系"));

#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 * FROM score WHERE cno = "3-105" and degree > ANY(SELECT degree FROM score WHERE cno = "3-245") 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 * FROM score WHERE cno = "3-105" and degree > (SELECT max(degree) FROM score WHERE cno = "3-245") ORDER BY degree DESC;

# 29、查询所有教师和同学的name、sex和birthday。

SELECT sname,ssex,sbirthday FROM student UNION SELECT tname,tsex,tbirthday FROM teacher;

# 30、查询所有“女”教师和“女”同学的name、sex和birthday。;

SELECT sname,ssex,sbirthday FROM student WHERE ssex = "女" UNION SELECT tname,tsex,tbirthday 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。

SELECT s.cno, s.degree FROM score s INNER JOIN (SELECT cno, AVG(degree) AS degree FROM score GROUP BY cno) c on c.cno = s.cno AND s.degree < c.degree;

# 32、查询所有任课教师的Tname和Depart。

SELECT Tname, Depart FROM teacher INNER JOIN course on teacher.tno = course.tno;

# 33、查询所有未讲课的教师的Tname和Depart。

SELECT Tname, Depart FROM teacher where tno not in (SELECT course.tno FROM score sc INNER JOIN course on sc.cno = course.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(Sno) >= 2;

# 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(NOW()) - YEAR(sbirthday)) AS age FROM student;

# 37、查询Student表中最大和最小的Sbirthday日期值。

SELECT Max(Sbirthday ),Min(Sbirthday ) 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;

# 39、查询“男”教师及其所上的课程。

SELECT cname FROM course WHERE tno in (SELECT tno FROM teacher WHERE tsex = "男" );

# 40、查询最高分同学的Sno、Cno和Degree列。

SELECT Sno,Cno,Degree FROM score ORDER BY degree DESC LIMIT 0,1;

# 41、查询和“李军”同性别的所有同学的Sname。

SELECT Sname FROM student WHERE ssex in (SELECT s.ssex FROM student s WHERE s.sname = "李军" ) and sname != "李军";

# 42、查询和“李军”同性别并同班的同学Sname。

SELECT Sname FROM student WHERE ssex in (SELECT s.ssex FROM student s WHERE s.sname = "李军" ) and class in (SELECT s.class FROM student s WHERE s.sname = "李军") and 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 sc.sno, sc.cno, sc.Degree FROM score sc INNER JOIN student s on s.sno = sc.sno WHERE s.ssex = "男" and cno = (SELECT cno FROM course WHERE cname = "计算机导论")；

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posted @ 2021-02-21 15:54 檀潇兵阅读(1530) 评论(0) 编辑收藏举报

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MySQL查询练习（适合mysql查询基础弱的同学，含答案）

1. 建表语句

2. 插入数据

3. 查询练习

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