Mysql练习题

练习题：

create database shujuku
use shujuku
create table student
(
    sno char(3) not null primary key,
    sname char(8) not null,
    ssex char(2) not null,
    sbirthday datetime,
    class char(5)
)

create table course
(
    cno char(5) not null primary key,
    cname varchar(10) not null,
    tno char(3) not null references teacher(tno)
)


create table score
(
    sno char(3) not null references student(sno),
    cno char(5) not null references course(cno),
    degree decimal(4,1),
    primary key(sno,cno)
)


create table teacher
(
    tno char(3) not null primary key,
    tname char(4) not null,
    tsex char(2) not null,
    tbirthday datetime ,
    prof char(6),
    depart varchar(10) not null
)


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','1976-01-23',95033)
insert into student values(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)
select *from student
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)
select *from course
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)
select *from score
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')
select *from teacher


----按照1、4、2、3的顺序创建表、添加数据；
---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
select *from score where degree>=60 and degree<=80

----5、查询score表中成绩为85,86或88的记录。
select *from score where degree=85 or degree=86 or degree=88
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 asc,degree desc
--注意前后顺序


----9、 查询“95031”班的学生人数。
select COUNT(*)as 个数 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 top 1 *from score order by degree desc 

select sno,cno from score where degree=(select MAX(degree)from score)

----11、 查询每门课的平均成绩。
select AVG(degree) as 平均, cno 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) as 平均分 from score  where cno like '3%' group by cno having count(*)>=5 
--having 必须跟在group by 后面


----13、查询分数大于70，小于90的Sno列。
select sno from score where degree>70 and degree<90

----14、查询所有学生的Sname、Cno和Degree列。
select sname, cno , DEGREE from student  join score on student.sno=score.sno
--左联接，结果包含第一个表中的行：就是留下student.sno
select (select sname from student where student.sno=score.sno),
cno,DEGREE from score
--子查询
select sname,cno,DEGREE from student,score where score.sno=student.sno
--表链接，笛卡尔积


----15、查询所有学生的Sno、Cname和Degree列。
select sno, cname, DEGREE from course  join score on course.cno=score.cno


----16、查询所有学生的Sname、Cname和Degree列。
select sname,cname,DEGREE from score join course on score.cno=course.cno join student on student.sno = score.sno
 

----17、 查询“95033”班学生的平均分。
select AVG(degree)as 平均分 from score where sno in (select sno from student where class=95033)

  select avg(degree) from score as c join student as s on c.sno = s.sno where s.class = '95033';

-----18、 假设使用如下命令建立了一个grade表：
create table grade
(
low  int,
upp  int,
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')
select *from grade
------现查询所有同学的Sno、Cno和rank列。
select *from score
select sno,cno,(select rank from grade where degree<=upp and degree>=low)as rank from score
select sno,cno,RANK from score join grade on degree between grade.low and grade.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
select *from student join score on score.sno=student.sno 
where cno='3-105' and degree >(select degree from score where sno='109'and cno='3-105')

　select t.* from score as c join student as t on c.sno=t.sno where c.cno='3-105' and c.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 *from score  where 
sno in (select sno from score group by sno having COUNT(*)>=2)and 
degree not in(select max(degree) from score )
--相关子查询
select *from score as a where a.sno in(select sno from score [as b] group by sno having COUNT(*)>1)and 
a.degree !=(select MAX(degree) from score as c where c.cno=a.cno)
--as a 必须有；as b和as c可以不用；



-----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 cno='3-105' and degree >(select degree from score where cno='3-105'and sno='109')


-----22、查询和学号为107的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
select sno,sname,sbirthday from student where YEAR(sbirthday)=(select YEAR(sbirthday) from student where sno='107')

----23、查询“张旭“教师任课的学生成绩。
select *from score where cno=(select cno from course where tno =(select tno from teacher where  tname='张旭'))

select s.*,t.tname from score as s join course as c on s.cno = c.cno join teacher as t on t.tno = c.tno where t.tname = '张旭';

1、查询考计算机导论的学生成绩

select s.* from score as s join course as c on c.cno=s.cno where c.cname = '计算机导论';

2、查询李诚老师教的课程名称

select c.* from course as c join teacher as t on t.tno = c.tno where t.tname = '李诚';

3、教高等数学的老师是哪个系的

select t.* from course as c join teacher as t on t.tno = c.tno where c.cname = '高等数学';

-----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 =(
select tno from course where cno=(
select cno from score group by cno having COUNT(*)>5))

select t.* from teacher as t join course as c on t.tno = c.tno where c.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='95033' or class='95031' 


----26、  查询存在有85分以上成绩的课程Cno.
select cno from score where degree >=85 group by cno

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。
select *from score where cno in(
select cno from course where tno in(select tno from teacher where   depart='计算机系'))

select s.* from score as s join course as c on s.cno = c.cno join teacher as t on t.tno = c.tno where t.depart = '计算机系';

----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='计算机系'and prof not in(select prof from teacher where depart ='电子工程系')
union--合并数据集
select tname,prof from teacher where depart='电子工程系'and prof not in(select prof from teacher where depart ='计算机系')

select tname,prof from teacher as a where (depart='计算机系' or 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 sno from score where cno='3-105' or cno='3-245' group by sno  having COUNT(*)>=2 
--select *from score where sno in('103','105','109')
select *from score where cno='3-105'and degree>(select degree from score where
 cno='3-245')order by degree desc

select a.* from score as a join score as b on a.sno = b.sno where a.cno = '3-105' and b.cno = '3-245' and a.degree>b.degree;

-----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.????
update score set degree=55 where sno='109'and cno='3-105'

select *from score where sno in (
select sno from score as a  where sno in(
select sno from score where cno='3-105'or cno='3-245'
group by sno having COUNT(*)>=2)
 and degree>(select degree from score where cno='3-245'--因为大于‘3-245’所以只显示‘3-105’可以省略cno='3-105'
and sno=a.sno)
)



----31、 查询所有教师和同学的name、sex和birthday.
 select sname as name,ssex as sex,sbirthday as birthday from student
union
select tname as name,tsex as sex,tbirthday as birthday from teacher

----32、查询所有“女”教师和“女”同学的name、sex和birthday.
 select sname as name,ssex as sex,sbirthday as birthday from student where ssex='女'
union
select tname as name,tsex as sex,tbirthday as birthday from teacher where tsex='女'
--列名按照上边的来



----33、 查询成绩比该课程平均成绩低的同学的成绩表。???
select cno from score group by cno 
select * from score where cno='3-105'and degree<(select AVG(degree) from score group by cno having cno='3-105')
union
select * from score where cno='3-245'and degree<(select AVG(degree) from score group by cno having cno='3-245')
union
select * from score where cno='6-166'and degree<(select AVG(degree) from score group by cno having cno='6-166')


select *from score as a
 where degree<
(select avg(degree)
from score as b 
where b.cno=a.cno)

1、查询所有成绩比3-105课程平均成绩低的同学的成绩表.

select * from score where degree <(select avg(degree) from score where cno = '3-105');

----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)

select t.tname,t.depart from teacher as t join course as c on c.tno=t.tno;

----35 、 查询所有未讲课的教师的Tname和Depart. 
select tname,depart from teacher where tno not in(select tno from course where cno in(select cno from score group by cno ))



----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(ssex)>=2 



----37、查询Student表中不姓“王”的同学记录。
select *from student where sname like '[^王]%'

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 as 姓名,(2015-(select YEAR(sbirthday)))as 年龄 from student



----39、查询Student表中最大和最小的Sbirthday日期值。
select MAX(sbirthday) as 最大,MIN(sbirthday) as 最小 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,(2015-(select YEAR(sbirthday)))desc,(13-(select month(sbirthday)))desc



----41、查询“男”教师及其所上的课程。
select tname ,cname from teacher  join course on teacher.tno=course.tno where tsex='男'


----42、查询最高分同学的Sno、Cno和Degree列。????
update score set degree=85 where sno='101'and cno='3-105'--原先分数是64

select * from score as a where degree=(select max(degree)from score where cno=a.cno)
select sno,cno,(select max(degree)from score  where cno=a.cno)from score as a---映射时一个个的写出；所以会出错
select * from score as a where degree in (select max(degree)from score group by cno)--会出现错误

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')
select a.* from student as a join student as b on a.ssex = b.ssex where b.sname = '李军';

----44、查询和“李军”同性别并同班的同学Sname.
select *from student
select sname from student where ssex=(select ssex from student where sname='李军')
and class=(select class from student where sname ='李军')

select a.* from student as a join student as b on a.ssex = b.ssex and a.class = b.class where b.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 degree 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')

select o.* from score as o join student as s on s.sno= o.sno join course as c on c.cno = o.cno where c.cname='计算机导论' and s.ssex = '男';