15-07-19数据库练习题答案

创建数据库，创建表

create database xiti

use xiti
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 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,
)

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),
)

select * from Student
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 Teacher
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 Course
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 Score
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)

 

习题答案

--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(*) 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）
方法一子查询、select Sno,Cno from Score where Degree = (select MAX(Degree) from Score)
方法二排序、select top 1 * from Score order by Degree desc

--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 cno,AVG(Degree) from Score group by Cno having COUNT(*)>=5 and Cno like '3%'

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

--17、 查询“95033”班学生的平均分。
方法一、select AVG(Degree)from Score join Student on Student.Sno=Score.Sno and Class='95033'
方法二、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 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,grade where Degree between low and upp

--19、 查询选修“3-105”课程的并且成绩高于“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 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。
--(1)找同学
select Sno from Score group by Sno having COUNT(*)>1
--(2)找最高分
select MAX(Degree) from Score where Sno in (select Sno from Score group by Sno having COUNT(*)>1)
--(3)去掉最高分
select Sno from Score where Degree !=(select MAX(Degree) from Score where Sno in (select Sno from Score group by Sno having COUNT(*)>1))group by Sno having COUNT(*)>1
--(4)找非最高分学生的信息
select * from Score where Sno in(select Sno from Score where Degree !=(select MAX(Degree) from Score where Sno in (select Sno from Score group by Sno having COUNT(*)>1))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 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。
--(1)求张旭的Tno
select Tno from Teacher where Tname='张旭'
--(2)根据Tno求Cno
select Cno from Course where Tno=(select Tno from Teacher where Tname='张旭')
--(3)根据Cno求学生成绩
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=(select Tno from Course where Cno=(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 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'))

--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 t2 where Depart='计算机系' and not exists(select * from Teacher t1 where Depart='电子工程系' and t1.Prof=t2.Prof)
union
select * from teacher t2 where Depart='电子工程系' and not exists(select * from Teacher t1 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 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.
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。
select * from Score s1 where Degree<(select AVG(Degree) from Score s2 group by Cno having s1.Cno=s2.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 distinct 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 not in (select Tno from Course where Cno 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,YEAR(GETDATE())- year(Sbirthday) desc

--41、查询“男”教师及其所上的课程。
方法一、select Cname,Tname from Course join Teacher on Course.Tno=Teacher.Tno where Tsex='男'

方法二、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 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=(select Ssex from Student where Sname='李军') and Sname !='李军'

--44、查询和“李军”同性别并同班的同学Sname.
方法一、select sname from Student where Ssex in(select Ssex from Student where Sname='李军' ) and Class = (select Class from Student where Sname = '李军') and Sname !='李军'

方法二、select Sname from Student s1 where Ssex=(select Ssex from Student s2 where Sname ='李军' and s1.Class=s2.Class) and 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。
方法一、select * 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')

方法二、select Score.Sno,Score.Cno,Degree from Score join Course on Score.Cno=Course.Cno join Student on Student.Sno =Score.Sno and Ssex='男' and Course.Cname='计算机导论'