45道题

create database practice
use practice
--学号 学生姓名 学生性别 生日 学生所在班级
create table student
(
sno nvarchar(50) primary key,
sname nvarchar(50) not null,
ssex nvarchar(50) not null,
sbirthday datetime null,
Class int null,
)
--课程号 课程名称 教工编号
create table Course
(
cno nvarchar(50) primary key,
cname nvarchar(50) not null,
tno nvarchar(50) not null,
)
--学号 课程号 成绩
create table Score
(
sno nvarchar(50) not null,
cno nvarchar(50) not null,
Degree Decimal(4,1) null,
)
--教工编号 姓名 性别 出生年月 职称 教工所在部门
create table Teacher
(
tno nvarchar(50) not null,
Tname nvarchar(50) not null,
Tsex nvarchar(50) not null,
Tbirthday datetime null,
Prof nvarchar(50) null,
Depart nvarchar(50) 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 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

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

--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。
--第一种写法
select distinct depart from Teacher
--第二种写法
select Depart from Teacher group by Depart

--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 >= 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

--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(*) as '数量' 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 where degree = (select MAX(Degree) as '最高分' from Score )

--11、查询每门课的平均成绩。
select cno,AVG(Degree) as '平均成绩' 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。
--思路：找出以3开头的科目，并以cno为依据分组
-- 从中找出分组后个数大于5的组
-- 求目标组的平均值
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

--14、查询所有学生的Sname、Cno和Degree列。(用表连接中的三种横连接)
select (select sname from student where student.sno = score.sno),cno,degree from Score
select sname,cno,degree from student,Score where student.sno = score.sno
select sname,cno,degree from student inner 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,Score where Score.cno =Course.cno

--16、查询所有学生的Sname、Cname和Degree列。
select (select cname from Course where Course.cno = Score.cno),sname,degree from student,Score where student.sno = Score.sno

--17、查询“95033”班学生的平均分。
select AVG(degree) as '平均分数' 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,degree,[RANK] from Score,grade where degree >low and degree <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。
--找出选修‘3-105’课程的所有同学——》找出学号为109并且是选修的‘3-105’这一科目的同学的成绩
select *from student where sno in (
select sno 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 *from Score where Degree <(
select MAX(degree) from Score where sno in (
select sno from Score group by sno having COUNT(*)>1))
and 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 student where sno
in (select sno 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。
--得到学号为108的学生的生日里的年份——》查询同年出生的学生的sno sname sbrithday
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 degree 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。
--在teacher表中找出该教工编号对应的教师姓名（在course表中找出该门课程号对应的教工编号（在score表中找出选择的课程编号大于5的课程号码））
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 ='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 cno from Score where Degree
in(select Degree from Score where Degree >85)

--27、查询出“计算机系“教师所教课程的成绩表。
--从score表中查成绩（从course表中找到该课程所对应的科目号（从teacher表中找教计算机系的老师的教工编号））
select degree 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。
--找出计算机系中教师职位与电子工程系中不同的人的姓名和这个人的职位
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' )

--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科目成绩大于3-245科目最高分的学生的cno，sno，degree，并降序排列
select cno,sno,degree 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 cno,sno,degree 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.(用表连接中的纵连接)
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 as a where Degree < (select AVG(Degree) from Score as 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 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（*）>=2

--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。
--年龄=现在的年份-出生的年份
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 *,YEAR(GETDATE())-YEAR(sbirthday) from student order by Class,YEAR(GETDATE())-YEAR(sbirthday) desc

--41、查询“男”教师及其所上的课程。
select cname from Course where tno in (select tno from Teacher where Tsex like '男')

--42、查询最高分同学的Sno、Cno和Degree列。
select sno,cno,degree 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 in (select ssex from student where sname = '李军')

--44、查询和“李军”同性别并同班的同学Sname.
--同性别，同班
select sname from student where ssex
in (select ssex from student where sname = '李军')
and
Class
in (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 degree from Score where sno
in (select sno from student where ssex = '1')
and
cno
in (select cno from Course where cname = '计算机导论')