MySql练习题

一、学生表                                                                                            二、教师表

            

 

三、课程表                                                                   四、分数表

                      

 

2、练习题

一、查询Student表中的全部记录的Sname、Ssex和Class列。

mysql> select Sname,Ssex,Class from Student;

二、 查询教师全部的单位即不重复的Depart列 

mysql> Select Depart from teacher group by Depart;

mysql> select distinct depart from teacher;

三、 查询Student表的全部记录。

mysql> select * from student;

四、 查询Score表中成绩在60到80之间的全部记录

mysql> select * from Score where Degree > 60 and Degree<80;

mysql> select * from score where degree between 60 and 80;

五、 查询Score表中成绩为85，86或88的记录。

mysql> select * from Score where Degree = 85 or Degree=86 or Degree = 88;

mysql> select * from Score where Degree in (85,86,88);

 六、 查询Student表中“95031”班或性别为“女”的同窗记录。

mysql> Select * from Student where Class=95031 or Ssex = '女';

七、 以Class降序查询Student表的全部记录。 

mysql> Select * from Student order by Class desc;

   八、 以Cno升序、Degree降序查询Score表的全部记录。

mysql> Select * from (Select * from Score order by Cno) as s order by Degree desc;

mysql> select * from score ORDER BY cno asc,degree desc;

九、 查询“95031”班的学生人数。

mysql> Select count(1) from Student where Class = 95031;

十、 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）

mysql> Select Sno,Cno from Score where Degree = (Select max(Degree) from Score);

10.1查询Score表中除了每门课程最高分的学生学号和课程号。（子查询或者排序）

mysql> Select Sno,Cno from Score where Degree not in (Select max(Degree) from Score group by Cno);

十一、 查询每门课的平均成绩。

mysql> Select Cno,avg(Degree) from Score group by Cno;

十二、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。

mysql> Select Cno,avg(Degree) from group by Cno having count(1)>=5 and Cno like "3%";

mysql> Select Cno,avg(Degree) from Score group by Cno having count(1)>=5 and left(Cno,1)= "3";

• 增长： 查询Score表中至少有3名学生选修的不以3开头的课程的平均分数

mysql> Select Cno,avg(Degree) from Score group by Cno having count(Sno)>=3 and left(Cno,1)<>"3";

1三、查询分数大于等于70，小于等于90的Sno列。

• 注意：between and包含边界值

mysql> Select Sno from Score where Degree between 70 and 90;

• 增长：查询分数小于70，大于90的Sno列
• not between and不包含边界值

mysql> Select Sno from Score where Degree not between 70 and 90;

1四、查询全部学生的Sname、Cno和Degree列。

mysql> Select Sname,Cno,Degree from Student join Score on Student.Sno=Score.Sno;

1五、查询全部学生的Sno、Cname和Degree列。

mysql> Select Sno,Cname,Degree from Score join Course on Course.Cno=Score.Cno;

 1六、查询全部学生的Sname、Cname和Degree列。

mysql> Select Sname,Cname,Degree from Course join (Select Sname,Cno,Degree from Student join Score on Student.Sno=Score.Sno) as s on Course.Cno=s.Cno;

1七、 查询“95033”班学生的平均分。

• mysql> Select avg(Degree) from (Select Degree from Score join (Select Sno from Student where Class=95033) as s on Score.Sno = s.Sno) as d;

• mysql> Select avg(Degree) from Score where Sno in (Select Sno from Student where Class = 95033);

1八、现查询全部同窗的Sno、Cno和rank列

1九、查询选修“3-105”课程的,而且成绩高于“109”号同窗成绩的全部同窗的记录。

mysql> Select * from Score where Degree > (Select Degree from Score where Cno = "3-105" and Sno = 109) and Cno ="3-105";

2一、 查询成绩高于学号为“109”、课程号为“3-105”的成绩的全部记录。

mysql> Select * from Score where Degree > (Select Degree from Score where Cno = "3-105" and Sno = 109);

2二、查询和学号为108的同窗同年出生的全部学生的Sno、Sname和Sbirthday列。

mysql> Select Sno,Sname,Sbirthday from Student where year(Sbirthday) = (Select year(Sbirthday) from Student where Sno = 108);

2三、查询“张旭“教师任课的学生成绩。

mysql> Select Sno,Degree,Cno from Score where Cno in (Select Cno from Course where Tno in (Select Tno from Teacher where Tname = "张旭"));

2四、查询选修某课程的同窗人数多于5人的教师姓名。

mysql> Select Tname from Teacher where Tno in (Select Tno from Course where Cno in (Select Cno from Score group by Cno having count(1) > 5));

 2五、查询95033班和95031班全体学生的记录。

mysql> Select * from Student where Class in (95033,95031);

2六、  查询存在有85分以上成绩的课程Cno.

mysql> Select distinct Cno from Score where Degree > 85;

2七、查询出“计算机系“教师所教课程的成绩表。

mysql> select * from score where cno in (select cno from course where Tno in (select tno from teacher where depart = "计算机系"));

2九、查询选修编号为“3-105“课程且成绩至少高于一个选修编号为“3-245”的同窗的Cno、Sno和Degree,并按Degree从高到低次序排序。

mysql> Select Sno,Cno,Degree from Score where Cno = "3-105" and Degree > any(Select Degree from Score where Cno="3-245");

30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同窗的Cno、Sno和Degree.

mysql> Select Sno,Cno,Degree from Score where Cno = "3-105" and Degree > all(Select Degree from Score where Cno="3-245");

3一、 查询全部教师和同窗的name、sex和birthday.

select sname,ssex,sbirthday from student union all select tname,tsex,tbirthday from teacher;

3二、查询全部“女”教师和“女”同窗的name、sex和birthday.

mysql> Select s.Sname,s.ssex,s.sbirthday from (select sname,ssex,sbirthday from student union all select tname,tsex,tbirthday from teacher) as s where s.Ssex = "女";

(select sname,ssex,sbirthday from student where ssex = "女") union all (select tname,tsex,tbirthday from teacher where tsex = "女");

3三、 查询成绩比该课程平均成绩低的同窗的成绩表

 

Select * from Score s1 where Degree < (Select avg(degree) from score s2 group by cno having s1.cno=s2.cno);

 

3四、 查询全部任课教师的Tname和Depart

mysql> Select tname,depart from teacher where tno in (select distinct tno from course where cno in (select distinct cno from score group by cno));

3六、查询至少有2名男生的班号 

错误：

 

mysql> select s.class from (select * from student where ssex = "男") as s group by s.class having count(1);

 

正确：

 

select class from student where ssex='男' group by class having count(1) >=2

 

3七、查询Student表中不姓“王”的同窗记录

mysql> select * from student where left(sname,1) <>"王";

mysql> select * from student where sname not like '王%';

3八、查询Student表中每一个学生的姓名和年龄

mysql> select sname,year(now())-year(Sbirthday) as age from student;

3九、查询Student表中最大和最小的Sbirthday日期值。

mysql> select max(Sbirthday),min(Sbirthday) from student;

40、以班号和年龄从大到小的顺序查询Student表中的所有记录。

mysql> select * from student order by class desc,Sbirthday;

mysql> select * from student ORDER BY class,year(now())-year(sbirthday);

4一、查询“男”教师及其所上的课程。

mysql> select * from course where tno in (select tno from teacher where tsex = "男");

4二、查询最高分同窗的Sno、Cno和Degree列。

mysql> select sno,cno,degree from score where degree = (select max(degree) from score);

4三、查询和“李军”同性别的全部同窗的Sname.

mysql> Select sname from student where ssex = (select ssex from student where sname ="李军");

4四、查询和“李军”同性别并同班的同窗Sname.

mysql> Select sname from student where (ssex,class) in  (select ssex,class from student where sname ="李军");

4五、查询全部选修“计算机导论”课程的“男”同窗的成绩表.

 

mysql> select * 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"）

 

 

4七、查询各科选课总人数和及格人数，以以下形式显示：课程编号，课程名称，总人数，及格人数，按课程编号升序排列

 

select s.cno,cname,allnum,passnum from (select s1.cno,allnum,passnum from (select Cno,count(*) as allnum from score group by cno) as s1 join (select Cno,count(*) as passnum from score where degree >= 80 group by cno) as s2 on s1.cno=s2.cno) as s join course on s.cno=course.cno order by s.cno;