44道SQL数据库多表连查练习题！
Time will tell.
有4张表：学⽣表（Student）、课程表（Course）、成绩表（Score）、’教师信息表（Teacher）。表结构分别如下所⽰。⽤SQL语句创建表并完成相关题⽬。
⼀、数据库表结构
Student （学⽣表）
Course（课程表）
Score（成绩表）
Teacher（教师表）
⼆、数据库表数据
Student
Course
Score
分数数组词
Teacher
三、数据库表题⽬查询
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 scroe where degree>=60 and degree<=80
ormysql面试题sql语句多表联查
Select *from scroe where degree between 60 and 80
5、查询Score表中成绩为85，86或88的记录。
Select *from scroe 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’ || 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。（⼦查询或者排序）
Select sno,cno from score order by degree desc limit 0,1
Select sno,cno from score where degree=(select max(degree) from score)
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。
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 avg(degree),cno from scroe 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 from score where cno like’3%’group by cno having count(*)>=5
) group by cno
Like模糊查询 3%以3开头 having只能跟在group by 后⾯
13、查询分数⼤于70，⼩于90的Sno列。
Select sno from score where degree>70 and degree<90
Select sno from score where degree between 70 and 90
14、查询所有学⽣的Sname、Cno和Degree列。
Select (select Sname from student where student.sno=score.sno),cno,degree from score
//select *from a,b 笛卡尔积 所有可能性
Select Sname,Cno,degree from score join student on score.sno=student.sno
15、查询所有学⽣的Sno、Cname和Degree列。
select Sno,(select Cname from course where course.Cno=score.Cno),Degree from score
16、查询所有学⽣的Sname、Cname和Degree列。
select (select Sname from Student where student.Sno=Score.Sno),(select Cname from course where
weight什么词性course.Cno=score.Cno),Degree from score
17、 查询“95033”班学⽣的平均分。
Select avg(degree),Cno from score join student on student.sno=score.sno where cno in (select cno from score 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(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 join grade on score.degree>=low && score.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。
offsetleft什么意思select * from score where degree in (Select degree from score where Cno=’ 3-105’and degree>( Select degree from score where Sno=109&&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 sno,cno,degree from score where degree not in (select max(degree) from score group by sno) and sno in (select sno from score group by sno having count(cno)>1)
Select * from score a where degree <(select max(degree) from Score b where b.Cno=a.Cno) 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m绩的所有记录。
Select * from score where degree>(select degree from score where sno=109 && 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)
食肉动物食草动物还有什么动物23、查询“张旭“教师任的学⽣成绩。
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 where Tno in( Select Tno from course where
Cno in( 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=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 degree,cno,Sno 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 where prof not in(select prof from teacher where Depart=‘计算机系’ and prof in(select prof from teacher where Depart=‘电⼦⼯程系’))
学的Cno、Sno和Degree，并按Degree从⾼到低次序排序。?
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 * from score where cno=‘3-105’ and degree>any (select degree from score where cno=‘3-245’)order by degree desc
select * from score where cno=‘3-105’ and degree>all(select degree from score where cno=‘3-245’)
30、 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;
31、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’
32、 查询成绩⽐该课程平均成绩低的同学的成绩表。
Select Sno,Cno,degree from Score a where degree<( Select avg(degree) from score b where a.Cno=b.Cno)
33、查询所有任课教师的Tname和Depart.
select tname,depart from teacher a where exists (select * from course b =b.tno)
34 、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 not in( Select Cno from course where Cno not in (select Cno from score)))
35、查询⾄少有2名男⽣的班号。
220v微型小电机
Select class from Student where Ssex=’男’group by class having count(SSex)>=2
36.查询不姓王的同学信息
select * from student where sname not like’王_’;
37、查询Student表中每个学⽣的姓名和年龄。
Select Sname,(year(now())-year(Sbirthday)) from student
38、查询Student表中最⼤和最⼩的Sbirthday⽇期值。
select sname,sbirthday as 最⼤ from student where sbirthday =(select min (sbirthday) from student)
union
select sname,sbirthday as 最⼩ from student where sbirthday =(select max(sbirthday) from student)
39、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, (year(now())-year(Sbirthday)) desc
40、查询“男”教师及其所上的课程。
Select Cno from Score where Tno in（Select Tno from teacher where Tsex=’男’）
41、查询所有选修“计算机导论”课程的“男”同学的成绩表。
select * from score where degree=(select max(degree)from score);
42、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’);
43、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’);
44、查询所有选修“计算机导论”课程的“男”同学的成绩表.
select * from score where sno in(select sno from student where ssex=‘男’) and cno=(select cno from course where cname=‘计算机导论’);
絮叨

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