查询综合练习整理

  建表

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)
   
  )


  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)

 



 );

  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


)

create table Score
(
 Sno varchar(20) not null ,
  
  

 Cno varchar(20) not null,

Degree Decimal(4,1),

 primary key(Sno,Cno),#建两个主键叫联合主键

foreign key (Sno) references Student(Sno),#这样建外键才有效


foreign key (Cno) references Course (Cno)


)

录入信息
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‘,‘1976-01-023‘,‘95033‘),( ‘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‘)


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‘)

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‘)


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 (‘101‘,‘3-105‘,‘64‘)

insert into Score values (‘107‘,‘3-105‘,‘91‘)

insert into Score values(‘108‘,‘3-105‘,‘78‘);

insert into Score values(‘101‘,‘6-166‘,‘85‘);

insert into Score values(‘107‘,‘6-166‘,‘79‘);


insert into Score values(‘108‘,‘6-166‘,‘81‘)
#填入信息时一定按主从表的顺序建要不添加不上，要想建外键也是先建主表在建从表

查询Student表中的所有记录的Sname、Ssex和Class列。
 1.select Sname,Ssex,Class from Student

查询教师所有的单位即不重复的Depart列。
2.select distinct Depart from Teacher#去重

 查询Student表的所有记录。
3.select *from Student
查询Score表中成绩在60到80之间的所有记录
4.select*from Score where Degree between  ‘60 ‘and ‘80‘ 

select*from Score where Degree >‘60‘ and Degree<‘80‘# 不用加单引号
 查询Score表中成绩为85，86或88的记录。
5.select*from Score where Degree=‘85‘and Degree=‘86‘or Degree=‘88‘

select*from Score where Degree in(85,86,88)
 查询Student表中“95031”班或性别为“女”的同学记录。
6.select *from Student where Class=‘95031‘or Ssex=‘女‘
以Class降序查询Student表的所有记录。
7.select*from Student  order by Class desc
以Cno升序、Degree降序查询Score表的所有记录。
8.select*from Score order by Cno asc, Degree desc
查询“95031”班的学生人数。
9.select count(*) from Student where class=‘95031‘
 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）
10.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) 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 avg (Degree)from Score group by Cno having count(*)>5 and Cno like ‘3%‘

select avg(Degree) from Score where Cno in (select Cno from Score group by Cno having count(*)>5) and Cno like ‘3%‘ group by Cno
 


13、查询分数大于70，小于90的Sno列。

 select  Sno from Score  WHERE Degree>‘70 ‘and Degree<‘90‘

 select  sno from score  where Degree between ‘70‘and ‘90‘

14、查询所有学生的Sname、Cno和Degree列。

select Student.Sname,Score.Cno, Score.Degree from Student,Score



select Sname,Cno,Degree from Score join Student on Student.Sno = Score.Sno
 

15、查询所有学生的Sno、Cname和Degree列。
 select Student.Sno,Cname,Degree from Student, Course,Score where Student.Sno=Score.sno
 
 select Student.Sno, Course.Cname,Score.Degree from Student,Course,Score

select Sno,Cname,Degree from Score join Course on Score.Cno = Course.Cno
16、查询所有学生的Sname、Cname和Degree列。
 select Student.Sname,Course.Cname,Score.Degree from Student,Course,Score where Student.Sno=Score.Sno and Course.Cno=Score.Cno

 select Sname,Cname,Degree from Score join Student on Student.Sno = Score.Sno join Course on Score.Cno = Course.Cno
17、 查询“95033"班学生的平均分。

  
    select avg (Degree) from  Score where Sno in   (select Sno from Student where Class=‘95033‘)
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 Sno,cno,rank from Score join grade on Score.Degree between low and 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 cno=‘3-105‘and Sno=‘109‘)
  

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*from score a where Sno in (select sno from Score group by Sno having count(*)>1)and Degree not in ( select max (Degree)from Score b where b.Cno=a.Cno)#第一种理解 选多门课程的同学指一个同学选好几门 用到相关子查询

第二种理解 选多门课程的同学指多个同学从多门课程中选
select * from Score a where Sno in (select Sno from Score group by Sno having count(*)>1 )  and Degree not in (select max(Degree) from Score a where Sno in (select Sno from Score group by Sno having count(*)>1 ))

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 student.Sno, student.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。
    select Tname,Sname,degree from teacher, course,score, student where student.sno   =score.sno and teacher.Tno=course.Tno and  course.cno=score.cno and teacher.Tname=‘张旭‘

    select*from Score where cno in (select cno from course where tno=( select Tno from Teacher wherer 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。
      select Tname from Teacher where Tno in ( select Tno from course where Cno in( select Cno from Score group by Cno having count(*)>5))

25、查询95033班和95031班全体学生的记录。
 select *from Student where class in (‘95031‘,‘95033‘)
26、  查询存在有85分以上成绩的课程Cno.
select distinc 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 *from Course where Tno in (select Tno from Teacher where
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 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‘))


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*from Score where Cno =‘3-105‘and Degree> any  ( select 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> 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 select Tname,Tsex,Tbirthday from  Teacher
32、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‘
33、 查询成绩比该课程平均成绩低的同学的成绩表。
select*from  Score a where Degree<(select avg (Degree) from Score b where b.Cno=a.cno)


34、 查询所有任课教师的Tname和Depart.




 select Tname ,depart from Teacher where Tno in (select Tno from Course)

成绩表上：select Tname,depart from Teacher where Tno in(select Tno from Course where Cno in(select Cno from Score))
35 、 查询所有未讲课的教师的Tname和Depart.
select Tname,depart from Teacher where Tno in(select Tno from Course where Cno not in(select Cno from Score))
 
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 Sno not in (select Sno from Student where Sname like‘王%‘)
38、查询Student表中每个学生的姓名和年龄。
select Sname,YEAR (now())-year(Sbirthday) from Student

39、查询Student表中最大和最小的Sbirthday日期值。
select max(Sbirthday)from Student union select min(Sbirthday) from Student #这样写运行只有一个最大值得表拦

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, Sbirthday desc

41、查询“男”教师及其所上的课程。

select*from Teacher join Course on Teacher.Tno=Course.Tno where Teacher.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 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.

select Sname from Student where Ssex=(select Ssex from Student where sname=‘李军‘)and class=(select 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。
  

select * from Score where Sno in (select Sno from Student where Ssex=‘男‘)and Cno in(select Cno from Course where Cname=‘计算机导论‘)