create database mydb3
go
use mydb3 
create table student
(
    --学号
    sno varchar(3) not null primary key,
    --姓名
    sname varchar(4) not null,
    --性别
    ssex varchar(2) not null,
    --出生年月
    sbirthday datetime,
    --所在班级
    class varchar(5)
)
create table teacher
(
    --教工编号
    tno varchar(3) not null primary key,
    --教工姓名
    tname varchar(4) not null,
    --教工性别
    tsex varchar(2) not null,
    --教工出生日期
    tbirthday datetime,
    --职称
    prof varchar(6),
    --所在部门
    depart varchar(10)
)

create table course
(
    --课程号
    cno varchar(5) not null primary key,
    --课程名称
    cname varchar(10) not null,
    --教工编号
    tno varchar(3) references teacher(tno)
)

create table score
(
    --学号
    sno varchar(3) not null references student(sno),
    --课程号
    cno varchar(5) not null references course(cno),
    --成绩
    degree decimal(4,1)
)


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‘)

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‘,‘1958-08-14‘,‘助教‘,‘电子工程系‘)

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 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 student
select * from teacher
select * from course
select * from score

--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(*) ‘人数‘ from student 
    where class=‘95031‘

--10、查询Score表中的最高分的学生学号和课程号。
select sno,cno from score 
    where degree=
    (
    select MAX(degree) from score
    )

--11、查询‘3-105’号课程的平均分。
select AVG(degree) from score
    where cno=‘3-105‘

--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
    where cno=
    (
    select cno from score
        where cno like ‘3%‘ 
        group by cno 
        having COUNT(*)>5
    )

--13、查询最低分大于70，最高分小于90的Sno列。
select sno from score
    group by sno
    having MIN(degree)>70 and MAX(degree)<90

--14、查询所有学生的Sname、Cno和Degree列。
select student.sname,score.cno,score.DEGREE from score
    join student on student.sno=score.sno

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

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

--17、查询‘95033‘班所选课程的平均分。
select AVG(degree) from score    
    where sno in
    (    
    select sno from student
        where class=‘95033‘
    )
    group by cno
    
--18、假设使用如下命令建立了一个grade表：
create table grade(low  int,upp  int,rank  varchar(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 distinct 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 student
    where sno in
    (
    select sno 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
    where cno not in
    (
    select cno from score
        where degree=
        (
        select MAX(degree) from score
        )
    )
    and cno in
    (
    select cno from score
        group by cno
        having COUNT(cno)>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 cno=‘3-105‘ and 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。
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。
select score.* from score
    join course on score.cno=course.cno
    join teacher on course.tno=teacher.tno
    where tname=‘张旭‘

select score.* from score,course,teacher
    where score.cno=course.cno
    and course.tno=teacher.tno
    and 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 distinct tname from teacher
    join course on course.tno=teacher.tno
    join score on score.cno=course.cno
    where score.cno=
        (
        select cno from score
            group by cno
            having COUNT(cno)>5
        )

--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 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 distinct score.* from score
    join course on course.cno=score.cno
    join teacher on teacher.tno=course.tno
    where teacher.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 * from teacher t1 where depart=‘计算机系‘ and  not exists
(
select * from teacher t2 where depart = ‘电子工程系‘ and t1.prof = t2.prof
)
union
select * from teacher t1 where depart=‘电子工程系‘ and  not exists
(
select * from teacher t2 where depart = ‘计算机系‘ and t1.prof = t2.prof
)
--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 >
(
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 s1 where sno in
(
select sno from score where cno in (‘3-105‘,‘3-245‘) group by sno having COUNT(*) > 1
) and cno = ‘3-105‘ and degree >
(
select degree from score s2 where sno in
(
select sno from score where cno in (‘3-105‘,‘3-245‘) group by sno having COUNT(*) > 1
) and cno = ‘3-245‘ and s1.sno = s2.sno
)
--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。
--求每门课的平均分
--求低于平均分的成绩
select * from score  s1 where degree <
(
select cno,AVG(degree) from score s2 where s1.cno = s2.cno  group by cno 
)

--34、查询所有任课教师的Tname和Depart.
select distinct tname,depart from teacher
    
--35  查询所有未讲课的教师的Tname和Depart. 
select tname ,depart  from teacher 
  left join course on teacher .tno  =course .tno 
  left join score on course .cno = score.cno 
  where score .sno is null
  
  
  select tname,depart from teacher where tno in
  (
  select * from course where cno not in
  (
  select distinct 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 sname not like ‘王%‘

--38、查询Student表中每个学生的姓名和年龄。
select sname,year(GETDATE())-year(sbirthday) 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,sbirthday asc

--41、查询‘男‘教师及其所上的课程。
select course.* 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。
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 student.* from score
    join course on course.cno=score.cno
    join student on student.sno=score.sno
    where course.cname=‘计算机导论‘ and ssex=‘男‘

--46、查询score表中分数最高的学生的信息。
select * from student
    where sno=
    (
    select sno from score
        where degree=
        (
        select MAX(degree) from score
        )
    )

--47、查询score表中的平均分在80分以上的学生信息。
select * from score 
select * from student 
select * from student where sno in
(
select sno from score group by sno having AVG (degree )>80
)