mysql数据库自测题-----多表查询习题
1.根据表的结构创建以下四个表
表一. student（学生表）
表二. teacher（教师表）
表三. course（课程表）
表四. score（成绩表）
2.分别向以上四个表中插入如下数据
Student表：
Sno Sname Ssex Sbirthday class
108 曾华 男 1977-09-01 95033
105 匡明 男 1975-10-02 95031
107 王丽 女 1976-01-23 95033
101 李军 男 1976-02-20 95033
109 王芳 女 1975-02-10 95031
103 陆君 男 1974-06-03 95031
代码如下：
insert into student values('108','曾华','男','1977-09-01','95033'),('105','匡明','男','1975-10-02','95031'),('107','王丽','女','1976-01-23','95033'),('101','李军','男','1976-02-20','95033'),('109','王芳','女','1975-02-10','95031'),('103','陆君','男','1974-06-03','95031');
Teacher表：
Tno Tname Tsex Tbirthday Prof Depart
804 李诚 男 1958-12-02 副教授 计算机系
856 张旭 男 1969-03-12 讲师 电子工程系
825 王萍 女 1972-05-05 助教 计算机系
831 刘冰 女 1977-08-14 助教 电子工程系
代码如下：
insert into teacher values('804','李诚','男','1958-12-02','副教授','计算机系'),('856','张旭','男','1969-03-12','讲师','电子工程系'),('825','王萍','女','1972-05-05','助教','计算机系'),('831','刘冰','女','1977-08-14','助 教','电子工程系');
Course表：
Cno Cname Tno
3-105 计算机导论 825
3-245 操作系统 804
6-166 数字电路 856
9-888 高等数学 831
代码如下：
insert into course values('3-105','计算机导论','825'),('3-245','操作系统','804'),('6-166','数字电路','856');
Score表：
Sno Cno Degree
103 3-245 86
105 3-245 75
109 3-245 68
103 3-105 92
105 3-105 88
109 3-105 76
101 3-105 64
107 3-105 91
108 3-105 78
101 6-166 85
107 6-166 79
108 6-166 81
代码如下：”
insert into score values('103','3-245',86),('105','3-245',75),('109','3-245',68),('103','3-105',92),('105','3-105',88),('109','3-105','76'),('101','3-105',64),('107','3-105',91),('108','3-105',78),('101','6-166',85),('107','6-166',79),('108','6-166',81);
3.查询‘95031’班级的学生数
select count(sname) from student where class=95031;
4.查询成绩表中的最高分的学生学号和课程号
select sno,cno,degree from score ORDER BY degree desc LIMIT 1
5.查询每门课的平均成绩
S
ELECT
Cname,
AVG(Degree)
FROM
course
LEFT JOIN score ON course.Cno = score.Cno
GROUP BY
Cname;
6.查询成绩表中至少有5名学生选修的并且以3开头的课程的平均分数
select cno,count(sno),avg(degree) from score group by cno having count(sno)>5;
7.查询所有学生的sname，cno，degree的列
select sname,cno,degree from student as s LEFT JOIN score as c on s.Sno=c.Sno;
8.查询95033班级学生的平均分
select avg(s.Degree) as '平均分' from score as s LEFT JOIN student s1 on s.Sno=s1.Sno where Class=95033;
9.查询张旭教师任课的学生成绩
SELECT Sname, Degree FROM teacher AS t INNER JOIN course AS c INNER JOIN score AS s INNER JOIN student AS s2 ON t.Ton = c.Tno AND s.Cno = c.Cno AND s.Sno = s2.Sno AND Tname = '张旭'
10.查询选修某课程的同学人数多于5人的教师姓名
select te.tname from teacher as te INNER JOIN course co INNER JOIN score sc INNER JOIN student st ON
te.Ton=co.tno and co.cno=sc.cno and sc.sno=st.sno
GROUP BY te.tname having count(te.tname)>5;
或者：
select te.tname from teacher as te INNER JOIN course co INNER JOIN score sc INNER JOIN student st ON
te.Ton=co.tno and co.cno=sc.cno and sc.sno=st.sno
GROUP BY sc.cno having count(sc.sno)>5;
11.查找计算机系教师所教课程的成绩表
SELECT tname, sname,degree FROM teacher AS t INNER JOIN course AS c INNER JOIN score AS s INNER JOIN student AS s2 ON t.Ton = c.Tno AND s.Cno = c.Cno AND s.Sno = s2.Sno AND Depar='计算机系'
12.查询所有选修‘计算机导论’课程的‘男’同学的成绩表
SELECT Sname,Degree FROM teacher AS t INNER JOIN course AS c INNER JOIN score AS s INNER JOIN student AS s2 ON t.Ton = c.Tno AND s.Cno = c.Cno AND s.Sno = s2.Sno AND Cname = '计算机导论'
and Ssex='男';