create database mydb
go
use mydb
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。

--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 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
--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。
select top 1 sno,cno from score order by degree desc

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

select AVG(degree) 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,MAX(degree),MIN(degree) from score group by sno having MAX(degree) < 90 and MIN(degree)>70

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

--16、查询所有学生的Sname、Cname和Degree列。
select sname,cname,degree from student 
    join score on student.sno = score.sno
    join course on score.cno = course.cno
--17、查询“95033”班所选课程的平均分。
select AVG(degree) from student
    join score on student.sno = score.sno
where class = ‘95033‘

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,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 * from score
select * from grade
select sno,cno,rank from score
    join grade on 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。//无关子查询
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。 //相关子查询
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 a.cno = b.cno  group by cno 
)
--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 * from student where year(sbirthday) =
(
    select year(sbirthday) from student where sno = ‘109‘
)
--23、查询“张旭“教师任课的学生成绩。
select * from teacher 
    join course on teacher.tno = course.tno
    join score on course.cno = score.cno
where tname=‘张旭‘

select * from score where cno  =
(
    select cno from course where tno = 
    (
        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。

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 (‘95033‘,‘95031‘)

select * from student where class=‘95033‘
union
select * from student where class=‘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

select cno from score group by cno having MAX(degree) >85

--27、查询出“计算机系“教师所教课程的成绩表。
select * from teacher
select * from course
select * from score

select score.sno,score.cno,score.degree from teacher 
    join course on teacher.tno = course.tno
    join score on course.cno = score.cno
where depart= ‘计算机系‘

select * from score where cno in
(
    select cno from course where tno in
    (
        select tno from teacher where 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。 //相关子查询
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。
--查询3-105大于3-245最高份的所有的成绩记录
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.//相关子查询

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 tname,tsex,tbirthday from teacher
union
select sname,ssex,sbirthday from student
--32、查询所有“女”教师和“女”同学的name、sex和birthday.
select tname,tsex,tbirthday from teacher where tsex=‘女‘
union
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。 //相关子查询
--求每门科的平均分
--求成绩低于平均分的成绩
select * from score s1 where degree <
(
    select 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 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 tno 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‘

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。
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 * from student where ssex=
(
    select ssex from student where sname=‘李军‘
)
and class=
(
    select class from student where sname=‘李军‘
)

select * from student s1 where ssex=
(
    select ssex from student s2 where 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 student.* from score 
    join course on score.cno = course.cno
    join student on score.sno = student.sno
where cname = ‘计算机导论‘ and ssex=‘男‘

select * from student where ssex=‘男‘ and sno in
(
    select sno from score where cno in
    (
        select cno from course where cname=‘计算机导论‘
    )
)
--46、查询score表中分数最高的学生的信息。//多层嵌套
select * from student where sno in 
(
    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。//无关查询

select * from student where sno in
(
    select sno from score group by sno having AVG(degree)>80
)