#建学生信息表student create table student ( sno varchar(20) not null primary key, sname varchar(20) not null, ssex varchar(20) not null, sbirthday datetime, class varchar(20) ); #建立教师表 create table teacher ( tno varchar(20) not null primary key, tname varchar(20) not null, tsex varchar(20) not null, tbirthday datetime, prof varchar(20), depart varchar(20) not null ); #建立课程表course create table course ( cno varchar(20) not null primary key, cname varchar(20) not null, tno varchar(20) not null, foreign key(tno) references teacher(tno) ); #建立成绩表 create table score ( sno varchar(20) not null primary key, foreign key(sno) references student(sno), cno varchar(20) not null, foreign key(cno) references course(cno), degree decimal ); #添加学生信息 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'); #添加教师表 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'); #添加课程表 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'); #添加成绩表 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('103','3-105','64'); insert into score values('105','3-105','91'); insert into score values('109','3-105','78'); insert into score values('103','6-166','85'); insert into score values('105','6-166','79'); insert into score values('109','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。
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=85 or degree=86 or degree=88;
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 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 where degree=(select max(degree) from score);
11、 查询每门课的平均成绩。
select cno,avg(degree) from score group by cno;
详解--查询每门课的平均成绩--分组和聚合结合的时候，先分组，然后对每一组分别进行聚合 Select AVG(Degree) from Score group by Cno;--先按Cno分组，在对Cno聚合
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。
解法1：select * from score where cno in(select cno from score group by cno having count(*)>=5) and cno like '3%';
详解--select Cno,AVG(Degree) from Score where Cno like '3%' group by Cno having COUNT(*)>=5--筛选分组完了再对每一组进行AVG聚合，分完组之后相当于只剩下分完组的列
13、 查询分数大于70，小于90的Sno列。
select sno from score group by sno having min(degree)>70 and max(degree)<90
14、 查询所有学生的Sname、Cno和Degree列。
select student.sname,score.cno,score.degree from student,score where student.sno=score.sno;
详解--表连接，一定有主外键关系：都好隔开两个表形成笛卡尔积，再进行where筛选，通过表主外键关系筛选，where只是个筛选条件
15、查询所有学生的Sno、Cname和Degree列。
select score.sno,score.degree,course.cname from score,course where score.cno=course.cno;
16、 查询所有学生的Sname、Cname和Degree列。
解法1：select student.sname,score.degree,course.cname from student,score,course where score.cno=course.cno and score.sno=student.sno;
解法2：select Sname,Cname,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。
解法1：select avg(degree) from student,score where student.sno=score.sno and class='95033';
解法2：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(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。
解法1：select sno,cno,rank from score,grade where degree between low and upp order by rank;
解法2：select sno,cno,degree,[rank] from Score join grade on degree between low and upp order by [rank]--on后面加筛选条件 解法3：select Sno,Cno,(select [rank] from grade where Score.Degree between low and upp) as LV from Score order by Degree desc--子查询得到的结果必须唯一
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 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。
理解1：选学多门课程的同学中，分数小于所有学生中最高分：
1.select * from score where sno in（2）and degree<（3）
2.select sno from score group by sno having count(*)>1
3.select max(degree) from score where sno in（4）
4.select sno from score group by sno having count(*)>1
结合起来：select * from score where sno in(select sno from score group by sno having count(*)>1) and degree<(select max(degree) from score where sno in(select sno from score group by sno having count(*)>1));
理解2：选多门课程中，分数小于每门课程最高分的学生信息
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.select * from score where cno in () 2.select cno from course where tno=() 3.select tno from teacher where tname='张旭'
结合起来：
select * from score where cno in (select cno from course where tno=(select tno from teacher where tname='张旭'))
解法1：select teacher.tname,course.cno,score.degree from teacher,course,score where teacher.tno=course.tno and course.cno=score.cno and tname='张旭';
解法2：select degree from Score join Course on Score.Cno=Course.Cno join Teacher on Course.Tno=Teacher.Tno 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。
1.select tname from teacher where tno=() 2.select tno from course where cno=() 3.select cno from score group by cno having count(*)>5
联合起来：
select tname from teacher where tno=(select tno from course where cno=(select cno from score group by cno having count(*)>5))
解法1;select teacher.tname from teacher,score,course where teacher.tno=course.tno and course.cno=score.cno group by tname having count(*)>5 ;
解法2：select Tname from Teacher where Tno=(select Tno from Course where Cno=(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。
解法1：select * from student where class='95033' or class='95031';
解法2：select*from student inner join Score on Student.Sno=Score.Sno where Class in(‘95033’,‘95031’) 解法3：select *from Student,Score where Class in(95033,95031) and Student.Sno=Score.Sno
26、 查询存在有85分以上成绩的课程Cno.
select score.cno from score,course where score.cno=course.cno and degree>85;
select cno from score group by cno having max(degree)>85;
27、查询出“计算机系“教师所教课程的成绩表
解法1：select degree from teacher,score,course where teacher.tno=course.tno and course.cno=score.cno and teacher.depart='计算机系';
解法2：select *from Score where Cno in( select Cno from Course where Tno in (select Tno from Teacher where Depart='计算机系')) 解法3：select Sno,Score.Cno,Degree from Score join Course on Score.Cno=Course.Cno join Teacher on Course.Tno=Teacher.Tno 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。
解法1：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');
解法2：select tname,prof from teacher where prof not in (select prof from teacher where depart='电子工程系' and prof in (select prof from teacher where depart='计算机系')) and depart in ('计算机系','电子工程系') --查询两个系中教师相同职称名称，不在这里面的就是除去两个系都有的剩下的，见上面 select prof from teacher where depart='电子工程系' and prof 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”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。（any的用法）
解法1；select * from score where cno='3-105' and degree > (select min(degree) from score where cno='3-245')order by degree desc;
解法2：select * 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.（all的用法）
select * from score where cno='3-105' and degree > (select max(degree) from score where cno='3-245');
select * 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 as aa where degree<(select avg(degree) from score as bb where aa.cno=bb.cno);
解法2：详解--相关子查询--同一门学科的平均分,，每门学科低于自身平均分的 select * from score as a where a.degree< (select AVG(degree) from score as b where a.cno = b.cno group by cno)--相当于foreach列出每一门课的平均分 select * from score as a where a.degree< (select AVG(degree) from score as b group by cno having a.cno = b.cno)
34、 查询所有任课教师的Tname和Depart
解法1：select tname,depart from teacher where exists (select * from course where teacher.tno=course.tno);
解法2：select Tname,Depart from Teacher where Tno in(select distinct Tno from Course)
35 、 查询所有未讲课的教师的Tname和Depart.
解法1：select tname,depart from teacher where not exists (select * from course where teacher.tno=course.tno);
解法2：select Tname,Depart from Teacher where Tno in(select Tno from Course where Cno not in(select Cno from Score group by Cno)) 解法3：select Tname,Depart from Teacher where Tno not in(select Tno from Course)
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。
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( date(student.sbirthday)) ,min( date(student.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,date(sbirthday) asc;
41、查询“男”教师及其所上的课程。
解法1：select teacher.tname,teacher.tsex,course.cname from teacher,course where teacher.tno=course.tno and tsex='男';
解法2：select teacher.tno,tname,tsex,cname,cno 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 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 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.sname,score.degree from student,score,course where student.sno=score.sno and course.cno=score.cno and course.cname='计算机导论' and student.ssex='男';
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')
仓库表加练习题
create table 仓库表 ( 仓库号 varchar(50) primary key not null, 城市 varchar(50) not null, 面积 int not null ); insert into 仓库表 values ('wh1','北京',370); insert into 仓库表 values ('wh2','上海',500); insert into 仓库表 values ('wh3','广州',200); insert into 仓库表 values ('wh4','武汉',400);
create table 职工表 ( 仓库号 varchar(50) not null, 职工号 varchar(50) primary key not null, 工资 int not null, foreign key(仓库号)references 仓库表(仓库号) ); insert into 职工表 values ('wh2','e1',1220); insert into 职工表 values ('wh1','e3',1210); insert into 职工表 values ('wh2','e4',1250); insert into 职工表 values ('wh3','e6',1230); insert into 职工表 values ('wh1','e7',1250);
create table 供应商表 ( 供应商号 varchar(50) primary key not null , 供应商名 varchar(50) not null, 地址 varchar(50) not null ); insert into 供应商表 values ('s3','振华电子厂','西安'); insert into 供应商表 values ('s4','华通电子公司','北京'); insert into 供应商表 values ('s6','607厂','郑州'); insert into 供应商表 values ('s7','爱华电子厂','北京');
create table 订购单表 ( 职工号 varchar(50) not null, 供应商号 varchar(50) , 订购单号 varchar(50) not null, 订购日期 date, foreign key(职工号) references 职工表(职工号), foreign key(供应商号) references 供应商表(供应商号) ); insert into 订购单表 values ('e3','s7','or67','2001-6-23'); insert into 订购单表 values ('e1','s4','or73','2001-7-28'); insert into 订购单表 values ('e7','s4','or76','2001-5-25'); insert into 订购单表 values ('e6',null,'or77',null); insert into 订购单表 values ('e3','s4','or79','2001-6-13'); insert into 订购单表 values ('e1',null,'or80',null); insert into 订购单表 values ('e3',null,'or90',null); insert into 订购单表 values ('e3','s3','or91','2001-7-13');
--1.从职工关系中检索所有工资值。
select 工资 from 职工表;
--2.检索仓库关系中的所有记录。
select *from 仓库表;
--3.检索工资多于1230元的职工号。
select 职工号 from 职工表 where 工资>'1230';
--4.检索哪些仓库有工资多于1210元的职工。
select 仓库号, 职工号 from 职工表 where 工资>'1210';
--5.给出在仓库“wh1”或“wh2”工作，并且工资少于1250元的职工号。
select 职工号 from 职工表 where 仓库号 not like 'wh3' and 工资<'1250'
--6.找出工资多于1230元的职工号和他们所在的城市。
select 城市,职工号 from 仓库表 join 职工表 on 仓库表.仓库号=职工表.仓库号 where 工资>'1230'
--7.找出工作在面积大于400的仓库的职工号以及这些职工工作所在的城市。
select 城市,职工号 from 仓库表 join 职工表 on 仓库表.仓库号=职工表.仓库号 where 面积>'400'
--★8.哪些城市至少有一个仓库的职工工资为1250元。
select 城市 from 仓库表 where 仓库号 in (select 仓库号 from 职工表 where 工资='1250')
--9.查询所有职工的工资都多于1210元的仓库的信息。
select *from 仓库表 where 仓库号 in( select 仓库号 from 职工表 where 1210< all(select 工资 from 职工表 where 仓库表.仓库号=职工表.仓库号))
--10.找出和职工e4挣同样工资的所有职工。
select 职工号 from 职工表 where 工资 = (select 工资 from 职工表 where 职工号='e4') and 职工号 !='e4'
--11.检索出工资在1220元到1240元范围内的职工信息。
select*from 仓库表 join 职工表 on 职工表.仓库号=仓库表.仓库号 where 工资 between 1220 and 1240
--★12.从供应商关系中检索出全部公司的信息，不要工厂或其他供应商的信息。
select*from 订购单表 select *from 订购单表 a join 职工表 b on a.职工号=b.职工号 and 供应商号=any(select 供应商号 from 供应商表)
--13.找出不在北京的全部供应商信息。
select * from 供应商表 where 地址 !='北京'
--14.按职工的工资值升序检索出全部职工信息。
SELECT *from 职工表 order by 工资 asc
--15.先按仓库号排序，再按工资排序并输出全部职工信息。
select *from 职工表 order by 仓库号 asc , 工资 asc
--16.找出供应商所在地的数目。
select 地址,COUNT(*) from 供应商表 group by 地址 select COUNT(地址) from 供应商表
-17.求支付的工资总数。
select SUM(工资) from 职工表
--18.求北京和上海的仓库职工的工资总和。
select SUM(工资) from 职工表 where 仓库号 in (select 仓库号 from 仓库表 where 城市 in('北京','上海'))
--19.求所有职工的工资都多于1210元的仓库的平均面积。
select AVG(面积) from 仓库表 where 仓库号 in (select 仓库号 from 职工表 where 工资>'1210')
--20.求在wh2仓库工作的职工的最高工资值。
select max(工资) from 职工表 where 仓库号 like 'wh2'
--21.求每个仓库的职工的平均工资。
select AVG(工资) from 职工表 group by 仓库号
--22.求至少有两个职工的每个仓库的平均工资。
select AVG(工资) from 职工表 group by 仓库号 having COUNT(仓库号)>=2
--23.找出尚未确定供应商的订购单。
select *from 订购单表 where 供应商号 is null
--24.列出已经确定了供应商的订购单信息。
select *from 订购单表 where 供应商号 is not null
-25.查询供应商名。
select *from 供应商表
--★26.在订购单表中加入一个新字段总金额，说明完成该订购单所应付出的总金额数。
alter table 订购单表 add 订购金额 varchar(max);
-27.列出每个职工经手的具有最高总金额的订购单信息。
select MAX(订购金额) from 订购单表 group by 职工号
--28.检索哪些仓库中还没有职工的仓库的信息。
select *from 仓库表 where 仓库号 not in (select 仓库号 from 职工表)
--29.检索哪些仓库中至少已经有一个职工的仓库的信息。
select *from 仓库表 where 仓库号 in (select 仓库号 from 职工表 group by 职工号 having COUNT(职工号)>=1)
--★30.检索有职工的工资大于或等于wh1仓库中任何一名职工工资的仓库号。
select *from 仓库表 where 仓库号 in(select 仓库号 from 职工表 where 职工号 in (select 职工号 from 职工表 where 工资 >(select MIN(工资) from 职工表 where 仓库号 like 'wh1'))) select distinct 仓库号 from 职工表 where 工资>=any(select 工资 from 职工表 where 仓库号='wh1') and 仓库号!='wh1'
--★31.检索有职工的工资大于或等于wh1仓库中所有职工工资的仓库号。
select *from 仓库表 where 仓库号 in(select 仓库号 from 职工表 where 职工号 in (select 职工号 from 职工表 where 工资 >=(select MAX(工资) from 职工表 where 仓库号 like 'wh1'))) select 仓库号 from 职工表 where 工资>= all(select 工资 from 职工表 where 仓库号='wh1') and 仓库号!='wh1'