SQL练习之简单问题2（有答案）

题目：设有一数据库，包括四个表：学生表（Student）、课程表（Course）、成绩表（Score）以及教师信息表（Teacher）。

表（提示：在做题目不影响的条件下可以对自己不熟悉的数据类型自己可以适当的做调整。）：

表中的数据：

 

 

查询问题：

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 * 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 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(*) 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 from score order by Degree desc limit 1;

select Sno,Cno from score where Degree=(select max(Degree) from score);

11、 查询每门课的平均成绩。

select Cno,avg(Degree) Degree from score group by Cno;

select

c.Cname,

s.degree

from course c

join (select s1.Cno cno,avg(s1.Degree) degree from score s1 group by Cno) s

on c.Cno=s.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) Degree from score where Cno like '3%' group by Cno having count(*)>4;

select

s1.Cno Cno,

s1.a Degree

from (select Cno,avg(Degree) a,count(*) c from score where Cno like '3%' group by Cno) s1

where s1.c > 4;

13、查询分数大于70，小于90的Sno列。

select Sno from score where Degree between 70 and 90;

select Sno from score where Degree > 70 and Degree < 90;

14、查询所有学生的Sname、Cno和Degree列。

select s1.Sname,s2.Cno,s2.Degree from student s1 join score s2 on s1.Sno=s2.Sno;

15、查询所有学生的Sno、Cname和Degree列。

select s2.Sno,c1.Cname,s2.Degree from course c1 join score s2 on c1.Cno=s2.Cno;

16、查询所有学生的Sname、Cname和Degree列

select

s1.Sname,

c1.Cname,

s2.Degree

from score s2

join student s1

on s2.Sno = s1.Sno

join course c1

on s2.Cno = c1.Cno;

17、 查询“95033”班学生的平均分。

select avg(s1.Degree) from score s1 join student s2 on s2.Class = '95033' where s1.Sno = s2.Sno;

18、 假设使用如下命令建立了一个grade表：

create table grade(low  int(3),upp  int(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’)

现查询所有同学的Sno、Cno和rank列。

select s1.Sno,s1.Cno,g1.rank from score s1,grade g1 where s1.Degree between g1.low and g1.upp;

select distinct s1.Sno,s1.Cno,s2.rank from score s1

join (select * from grade)s2

on s1.Degree between s2.low and s2.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 score where Cno='3-105' and Degree > (select Degree from score where Sno='109' and Cno='3-105');

20、查询score中选学多门课程的同学中分数为非最高分成绩的记录。

select s1.Sno,s1.Cno,s1.Degree from score s1

join (select Sno,max(Degree) Degree from score group by Sno having count(*)>1)s2

on s1.Sno=s2.Sno and s1.Degree<>s2.Degree;

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 Sno='109' and Cno='3-105');

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 s1.Sno,s1.Sname,s1.Sbirthday

from student s1

join (select left(Sbirthday,4) birthday from student where Sno='108')s2

on left(s1.Sbirthday,4)=s2.birthday and s1.Sno<>'108';

23、查询“张旭“教师任课的学生成绩。

select s1.Degree

from course c1

join (select Tno from teacher where Tname='张旭') t1

on c1.Tno=t1.Tno

join score s1

on s1.Cno=c1.Cno;

24、查询选修某课程的同学人数多于5人的教师姓名。

select t1.Tname

from course c1

join (select Cno from score group by Cno having count(*) > 5) s1

on c1.Cno=s1.Cno

join teacher t1

on c1.Tno=t1.Tno;

25、查询95033班和95031班全体学生的记录。

select * from student where Class in('95033','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 s1.Degree

from course c1

join (select Tno from teacher where Depart='计算机系') t1

on c1.Tno=t1.Tno

join score s1

on s1.Cno=c1.Cno;

28、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 Depart in('计算机系','电子工程系');

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 Cno,Sno from score where Cno='3-105' and Degree >

(

select max(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 * from score where Cno='3-105' and Degree >

(

select max(Degree) from score where Cno='3-245'

)

31、 查询所有教师和同学的name、sex和birthday.

select

distinct

t.Tname,

t.Tsex,

t.Tbirthday,

s.Sname,

s.Ssex,

s.Sbirthday

from teacher t

inner join student s

on true;

32、查询所有“女”教师和“女”同学的name、sex和birthday.

select

distinct

t.Tname,

t.Tsex,

t.Tbirthday,

s.Sname,

s.Ssex,

s.Sbirthday

from teacher t

join student s

on t.Tsex='女' and s.Ssex='女'

 

select Tname,Tsex,Tbirthday from teacher where Tsex='女';

select Sname,Ssex,Sbirthday from student where Ssex='女';

33、 查询成绩比该课程平均成绩低的同学的成绩表。

select DISTINCT s1.Sno,s1.Cno,s1.Degree from score s1

join (select Cno,avg(Degree) Degree from score group by Cno) s2

on s1.Cno=s2.Cno and s1.Degree<s2.Degree

34、 查询所有任课教师的Tname和Depart.

select t.Tname,t.Depart

from course c

join (select Cno from score group by Cno)s

on c.Cno=s.Cno

join teacher t

on t.Tno=c.Tno

35 、 查询所有未讲课的教师的Tname和Depart.

select t.Tname,t.Depart

from course c

join teacher t

on c.Cno not in (select Cno from score group by Cno)

and c.Tno=t.Tno

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(*)>1

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,Ssex 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 * from student order by Class desc,Ssex desc;

41、查询“男”教师及其所上的课程。

select c.Cname

from course c

join teacher t

on t.Tsex='男' and t.Tno=c.Tno

select Cname 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。

select * 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 s1.Sname from student s1

join (select * from student where Sname = '李军')s2

on s1.Ssex=s2.Ssex and s1.Sname<>'李军';

44、查询和“李军”同性别并同班的同学Sname.

select s1.Sname from student s1

join (select * from student where Sname = '李军')s2

on s1.Ssex=s2.Ssex and s1.Sname<>'李军' and s1.Class=s2.Class;

45、查询所有选修“计算机导论”课程的“男”同学的成绩表。

select s1.Sno,s1.Cno,s1.Degree from score s1

join (select Cno from course where Cname='计算机导论') s2

on s1.Cno=s2.Cno

join (select Sno from student where Ssex='男') s3

on s1.Sno = s3.Sno;