1、学生表 2、教师表
3、课程表 4、分数表
二、练习题
1、查询Student表中的所有记录的Sname、Ssex和Class列。
mysql> select Sname,Ssex,Class from Student;
2、 查询教师所有的单位即不重复的Depart列
mysql> Select Depart from teacher group by Depart;
mysql> select distinct depart from teacher;
3、 查询Student表的所有记录。
mysql> select * from student;
4、 查询Score表中成绩在60到80之间的所有记录
mysql> select * from Score where Degree > 60 and Degree<80;
mysql> 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。
mysql> select * from Score where Degree = 85 or Degree=86 or Degree = 88;
mysql> 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。
mysql> Select * from Student where Class=95031 or Ssex = '女';
7、 以Class降序查询Student表的所有记录。
mysql> Select * from Student order by Class desc;
8、 以Cno升序、Degree降序查询Score表的所有记录。
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;
9、 查询“95031”班的学生人数。
mysql> Select count(1) 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）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);
11、 查询每门课的平均成绩。
mysql> 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。
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";
增加： 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";
13、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;
增加：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;
14、查询所有学生的Sname、Cno和Degree列。
mysql> 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。
mysql> Select Sno,Cname,Degree from Score join Course on Course.Cno=Score.Cno;
16、查询所有学生的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;
17、 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);
18、现查询所有同学的Sno、Cno和rank列
19、查询选修“3-105”课程的,并且成绩高于“109”号同学成绩的所有同学的记录。
mysql> Select * from Score where Degree > (Select Degree from Score where Cno = "3-105" and Sno = 109) and Cno ="3-105";
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。
mysql> 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。
mysql> Select Sno,Sname,Sbirthday from Student where year(Sbirthday) = (Select year(Sbirthday) from Student where Sno = 108);
23、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"));
24、查询选修某课程的同学人数多于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));
25、查询95033班和95031班全体学生的记录。
mysql> Select * from Student where Class in (95033,95031);
26、 查询存在有85分以上成绩的课程Cno.
mysql> Select distinct Cno from Score where Degree > 85;
27、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"));
29、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”的同学的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”课程的同学的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");
31、 查询所有教师和同学的name、sex和birthday.
select sname,ssex,sbirthday from student union all select tname,tsex,tbirthday from teacher;
32、查询所有“女”教师和“女”同学的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");
33、 查询成绩比该课程平均成绩低的同学的成绩表
Select * from Score s1 where Degree < (Select avg(degree) from score s2 group by cno having s1.cno=s2.cno);
34、 查询所有任课教师的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));
36、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
37、查询Student表中不姓“王”的同学记录
mysql> select * from student where left(sname,1) <>"王";
mysql> select * from student where sname not like '王%';
38、查询Student表中每个学生的姓名和年龄
mysql> select sname,year(now())-year(Sbirthday) as age from student;
39、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表中的全部记录。
mysql> select * from student order by class desc,Sbirthday;
mysql> select * from student ORDER BY class,year(now())-year(sbirthday);
41、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");
42、查询最高分同学的Sno、Cno和Degree列。
mysql> 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.
mysql> 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.
mysql> Select sname from student where (ssex,class) in (select ssex,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.
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"）
47、查询各科选课总人数和及格人数，以如下形式显示：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;