SQL数据库—<10>--查询练习题
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1 create database xxb 2 go 3 use xxb 4 go 5 --表（一）Student (学生表) 6 create table Student 7 ( 8 sno char(3) primary key, 9 sname char(8) not null, 10 ssex char(2) not null, 11 sbirthday datetime, 12 class char(5) 13 ) 14 go 15 --表（四）Teacher(教师表) 16 create table teacher 17 ( 18 tno char(3) primary key, 19 tname char(4) not null, 20 tsex char(2) not null, 21 tbirthday datetime not null, 22 prof char(6) not null, 23 depart varchar(10) not null 24 ) 25 select * from teacher 26 go 27 --表（二）Course（课程表） 28 create table course 29 ( 30 cno char(5)primary key, 31 cname varchar(10) not null, 32 tno char(3) references teacher(tno) --foreign key(tno) references teacher(tno) 33 )--references 34 go 35 --表（三）Score(成绩表) 36 create table score 37 ( 38 sno char(3) references Student(sno) not null, 39 cno char(5) references course(cno) not null, 40 degree decimal(4,1) 41 ) 42 use xxb 43 go 44 --向表中插入数据，顺序不能变 45 insert into Student values('108','曾华','男','1977-09-01','95033') 46 insert into Student values('105','匡明','男','1975-10-02','95031') 47 insert into Student values('107','王丽','女','1976-01-23','95033') 48 insert into Student values('101','李军','男','1976-02-20','95033') 49 insert into Student values('109','王芳','女','1975-02-10','95031') 50 insert into Student values('103','陆军','男','1974-06-03','95031') 51 52 53 54 insert into teacher values('804','李诚','男','1958-12-02','副教授','计算机系') 55 insert into teacher values('856','张旭','男','1969-03-12','讲师','电子工程系') 56 insert into teacher values('825','王萍','女','1972-05-05','助教','计算机系') 57 insert into teacher values('831','刘冰','女','1977-08-14','助教','电子工程系') 58 59 60 insert into course values('3-105','计算机导论','825') 61 insert into course values('3-245','操作系统','804') 62 insert into course values('6-166','数字电路','856') 63 insert into course values('9-888','高等数学','831') 64 65 insert into score values('103','3-245','86') 66 insert into score values('105','3-245','75') 67 insert into score values('109','3-245','68') 68 insert into score values('103','3-105','92') 69 insert into score values('105','3-105','88') 70 insert into score values('109','3-105','76') 71 insert into score values('101','3-105','64') 72 insert into score values('107','3-105','91') 73 insert into score values('108','3-105','78') 74 insert into score values('101','6-166','85') 75 insert into score values('107','6-166','79') 76 insert into score values('108','6-166','81')
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。 消除重复的行 用distinct 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>60 and degree<80 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='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 --asc是升序排列 默认可不写 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 --先按照cno升序再degree降序显示 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 top 1 sno,cno,degree from score order by degree desc 11、 查询每门课的平均成绩。(select Brand from Car group by brand ) select AVG(degree) as 每个平均成绩 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。 select cno ,AVG(degree) ,count(*)from score where cno like '3%' group by cno having COUNT (*) >=5 13、查询分数大于70，小于90的Sno列。 select sno,degree from score where degree between 70 and 90 14、查询所有学生的Sname、Cno和Degree列。 select sname,cno,degree from student join score on score.sno=student.sno --先将student表和score表join起来，然后查询需要的列 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 score join course on course.cno=score.cno select sno,cname,degree from score join course on score.cno=course.cno
16、查询所有学生的Sname、Cname和Degree列。
第一步写三个表,第二步join起来，第三步筛选需要的列
select sname,cname,degree from Student
join score on score.sno=Student.sno
join course on course.cno=score.cno
17、 查询“95033”班学生的平均分。
select avg(degree) from score
join Student on Student.sno=score.sno
where class='95033'
--或者：
select * from score
select * from Student
select sno from Student where class='95033'
select AVG(degree) from score where sno in ('101','107','108')
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 * from grade
select sno,cno,[rank] from score
join grade on degree between low and upp
select sno,cno,[rank] from score
--select * from grade
join grade on score.degree >=low and 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。--无关子查询
select distinct * from Student join score on score.sno=Student.sno
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'))
先用子查询查询出3-105课程和是109同学的成绩 在拿这个成绩加上3-105条件判断那个同学符合条件 并且筛选出他的学号 在学生表中查找符号条件的学号 输出学生所有信息
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。
外层条件拿到里层进行比较，符合条件的查询返回
找出选修多门课程的同学的sno；里层查询找出每门课程的最高分，前天条件是里层的cno和外层的cno一样
select sno from score group by sno having COUNT(*)>1
select MAX(degree) from score where
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
)
select sno from score where sno!=103 group by sno having COUNT(*)>1
select degree from score where sno in ('101','103','105','107','108','109')
select max(degree) from score
select sno from score where degree=92
select degree from score where sno in (select sno from score where sno!=(select sno from score where degree=(select max(degree) 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 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。
select degree from score where cno=(select cno from course where tno=(select tno from teacher where tname = '张旭'))
select * from score
join course on score.cno =course.cno
join teacher on course.tno=teacher.tno
where teacher.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
join course on teacher.tno=course.tno
where course.cno in(select cno from score group by cno having COUNT(*)>5 )
--或者
select tname from teacher where tno in(select tno from course where cno in(select cno from score group by cno having COUNT (*)>=5)
)
--步骤
select * from teacher
select * from score
select tno from course where cno in(select cno from score group by cno having COUNT (*)>=5)
select * 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'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
join course on score.cno=course.cno
join teacher on course.tno =teacher.tno
where depart='计算机系'
多余的 where course.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。
不用相关子查询
SELECT * FROM teacher where depart='计算机系' and prof NOT IN(SELECT prof from teacher where depart='电子工程系')
UNION
SELECT * FROM teacher where depart='电子工程系' and prof NOT IN(SELECT prof from teacher where depart='计算机系')
--相关子查询
SELECT * FROM teacher t1 where depart='计算机系' AND NOT EXISTS(
SELECT * FROM teacher t2 WHERE t2.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 t2.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 >
(select max(degree) from score where cno='3-245') order by degree desc
--步骤：
select * from score
select MAX(degree) from score where cno='3-245'
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.
select * from score
select sno from score where cno in('3-105','3-245') group by sno having COUNT(*)>1
select * from score where sno in(select sno from score where cno in('3-105','3-245') group by sno having COUNT(*)>1
)
select degree as a from score where sno in('103','105','109')and cno in ('3-105')
select degree as b from score where sno in('103','105','109')and cno in ('3-245')
select * from score a where degree in(select degree as a from score where sno in('103','105','109')and cno in ('3-105')) AND EXISTS(select degree as b from score where sno in('103','105','109')and cno in ('3-245')
)
答案
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 s2.sno=s1.sno
)
31、 查询所有教师和同学的name、sex和birthday.
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 AVG(degree) from score group by cno --对课程分类 取每类课程的平均成绩
select * from score as a where exists (select cno,AVG(degree) from score b group by cno having (a.cno=b.cno and a.degree<AVG(degree)))
select *from score s1 where degree<
(
select AVG(degree) from score s2 where s1.cno=s2.cno group by cno
)
select * from score a1 where degree<(
select AVG(degree) from score a2 where a1.cno=a2.cno group by cno )
select * from score a where exists ( select cno,AVG(degree) from score b group by cno having (a.sno=b.sno) and (a.degree<avg(degree)))
34、 查询所有任课教师的Tname和Depart.
select tname,depart from teacher
select * from teacher a where exists (select * from course b where a.tno=b.tno )
或者
select * from teacher where tno in(select distinct tno from course
)
或者
--------select * from teacher a left join course b on a.tno=b.tno where course.tno is null
35 、 查询所有未讲课的教师的Tname和Depart.
答案之一：1、先把score表中cno分组出来（实际学生上了那些课）；2、拿course表中的cno给步骤1的结果做比较 not in （course表中cno是老师要讲的课，跟学生实际上了那些课做比较，得出哪门课程是学生没有上的）3、已经获得未讲的课的编号，把teacher表和course表join起来 从中找到这门课是哪个老师的课程
select tname,depart from teacher
join course on teacher.tno=course.tno
where course.cno=(select cno from course where cno not in(select cno from score group by cno))
答案2:
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
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--行数>1 说明
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 like '王%'
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) as 年龄 from Student --getdate()是获得当前时间的函数
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) as 年龄 from Student order by class desc, sbirthday
41、查询“男”教师及其所上的课程。
select tname,tsex,course.cname from teacher
join course on teacher.tno=course.tno 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,ssex 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 sname,ssex,class from Student where ssex=(select ssex from Student where sname='李军') and class=(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 student.sno,course.cno,degree,sname,ssex,class,cname,tno from score
join Student on score.sno=Student.sno
join course on score.cno=course.cno
where cname='计算机导论' and ssex ='男'