MySQL强化练习答案

it2024-07-14  76

1、题目

题目:设有一数据库,包括四个表:学生表(Student)、课程表(Course)、成绩表(Score)以及教师信息表(Teacher)。四个表的结构分别如表1-1的表(一)~表(四)所示,数据如表1-2的表(一)~表(四)所示。用SQL语句创建四个表并完成相关题目。

2、数据库的表结构

2.1、表1:Student (学生表) 

1 create table student 2 ( 3 sno varchar(20) not null primary key, 4 sname varchar(20) not null, 5 ssex varchar(20) not null, 6 sbirthday datetime, 7 class varchar(20) 8 );

2.2、表2:Teacher(教师表)

1 create table teacher 2 ( 3 tno varchar(20) not null primary key, 4 tname varchar(20) not null, 5 tsex varchar(20) not null, 6 tbirthday datetime, 7 prof varchar(20), 8 depart varchar(20) not null 9 );

2.3、表3:Course(课程表)

1 create table course 2 ( 3 cno varchar(20) not null primary key, 4 cname varchar(20) not null, 5 tno varchar(20) not null, 6 foreign key(tno) references teacher(tno) 7 );

2.4、表4:Score(成绩表)

1 create table score 2 ( 3 sno varchar(20) not null, 4 foreign key(sno) references student(sno), 5 cno varchar(20) not null, 6 foreign key(cno) references course(cno), 7 degree decimal 8 );

 3、数据库中的数据

 3.1、Student(学生表)

 

1 insert into student values('108','曾华','','1977-09-01','95033'); 2 insert into student values('105','匡明','','1975-10-02','95031'); 3 insert into student values('107','王丽','','1976-01-23','95033'); 4 insert into student values('101','李军','','1976-02-20','95033'); 5 insert into student values('109','王芳','','1975-02-10','95031'); 6 insert into student values('103','陆君','','1974-06-03','95031');

3.2、Teacher(教师表)

insert into teacher values (804,'李成','','1958-12-2','副教授','计算机系'); insert into teacher values (856,'张旭','','1969-3-12','讲师','电子工程系'); insert into teacher values (825,'王萍','','1972-5-5','助教','计算机系'); insert into teacher values (831,'刘冰','','1977-8-14','助教','电子工程系');

3.3、Course(课程表)

 

1 insert into course values('3-105','计算机导论','825'); 2 insert into course values('3-245','操作系统','804'); 3 insert into course values('6-166','数字电路','856'); 4 insert into course values('9-888','高等数学','831');

 3.4、Score(成绩表)

1 insert into score values('103','3-245','86'); 2 insert into score values('105','3-245','75'); 3 insert into score values('109','3-245','68'); 4 insert into score values('103','3-105','92'); 5 insert into score values('105','3-105','88'); 6 insert into score values('109','3-105','76'); 7 insert into score values('103','3-105','64'); 8 insert into score values('105','3-105','91'); 9 insert into score values('109','3-105','78'); 10 insert into score values('103','6-166','85'); 11 insert into score values('105','6-166','79'); 12 insert into score values('109','6-166','81');

4、45小题答案

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='' 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。(子查询或者排序)查询语句查询出一个或者一列结果,可以作为其他查询语句的参数来使用,就是子查询,就是查询的嵌套。 select Sno,Cno from Score where Degree=(select max(Degree) from Score) select Sno,Cno from Score order by Degree desc limit 0,1 11、查询每门课的平均成绩,要按照课程分组group by,然后求没门课平均avg 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。Like模糊查询 3%以3开头 having只能跟在group by 后面 SELECT AVG(Degree) FROM score where Cno LIKE '3%' GROUP BY Cno HAVING count(1)>5  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 Score , student where Score.Sno=student.Sno 15、查询所有学生的Sno、Cname和Degree列。 select Sno,Cname,Degree from Score , Course where Score.Cno=Course.Cno 16、查询所有学生的Sname、Cname和Degree列。 select Sname,Cname,Degree from student,course,score where student.Sno=score.Sno and course.Cno=score.Cno select Sname,Cname,Degree from student join score on student.Sno=score.Sno join course on course.Cno=score.Cno 17、 查询“95033”班学生的平均分。 select avg(degree) as 'class=95033' 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,rank from Score,grade where 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 score where Cno='3-105' and degree>(select max(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 a where Sno in (select Sno from score group by Sno having count(*)>1) and degree<( select max(degree ) from Score b where b.cno = a.cno) 21、查询成绩高于学号为“109”、课程号为“3-105”的成m绩的所有记录。 Select * from score where degree>(select degree from Score where Sno='109' and Cno='3-105' order by degree desc limit 1 ) 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') select sno,sname,sbirthday from student where year(sbirthday) = (select year(sbirthday) from student where sno='101') 23、查询“张旭“教师任的学生成绩。 select Sno,degree from score,Course where score.Cno=Course.Cno and Course.Tno= (select Tno from Teacher where Tname='张旭' ) select degree from score where Cno in (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, Course where Teacher.Tno=Course.Tno and Course.Cno =(select Cno from Score group by Cno having count(*)>5) 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 in ('95033','95031') 26、 查询存在有85分以上成绩的课程Cno. select 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 course 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 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')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') 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 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' ) order by degree desc 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='' union select Sname,Ssex,Sbirthday from Student where Ssex='' 33、 查询成绩比该课程平均成绩低的同学的成绩表。 select * from score a where degree < (select avg(degree) from score 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 ) 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 )) 36、查询至少有2名男生的班号。 select class from student where ssex='' group by class having count(*)>1 37.查询不姓王的同学信息 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(now())-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 41、查询“男”教师及其所上的课程。 select Tname,Cname from course,teacher where course.tno= teacher.tno and teacher.Tsex='' 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) 排序写法:select Sno,Cno,Degree from score order by degree desc limit 0,1 43、查询所有选修“计算机导论”课程的“男”同学的成绩表。 SELECT * from score JOIN course ON course.Cno=score.Cno AND Cname='计算机导论' join student ON student.Sno=score.Sno AND Ssex='' 44、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') 45、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') 46、查询所有选修“计算机导论”课程的“男”同学的成绩表。 select Sno,Cno,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=''

转载于:https://www.cnblogs.com/combat/p/9566116.html

相关资源:2020年计算机二级MySQL考试经典强化练习及答案.doc
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