Orcle数据库查询练习复习：一

一、创建数据库和表

drop table student;
create table student
(
  sid int,
  sname varchar2(100),
  sage int,
  ssex char(3),
  snativeplace varchar2(100),
  smajor varchar2(100),
  sclass varchar2(100),
  snative varchar2(100)
);
drop table course;
create table course
(
  cid int,
  cname varchar2(100),
  cval int,
  ctime int,
  tid int
);
drop table mark;
create table mark
(
  sid int,
  cid int,
  cmark int
);
drop table teacher;
create table teacher
(
  tid int,
  tname varchar2(100),
  tsex char(3),
  tage int,
  tlvl varchar2(100)
);
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10001,'廖官忠',21,'男','福建','信计','2班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10002,'张三',20,'男','江苏','信计','2班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10003,'李四',19,'男','福建','信计','2班','傣族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10004,'萧瑾',21,'女','福建','统计','1班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10005,'叶晶',21,'女','上海','传煤','1班','朝鲜族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10006,'萧瑾',19,'女','北京','统计','2班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10007,'李宁',21,'男','云南','信控','1班','傣族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10008,'唐品',18,'男','江苏','信计','2班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10009,'吴强',20,'男','山东','统计','1班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10010,'欧阳锋',22,'男','四川','应数','1班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10011,'王充样',23,'男','黑龙江','统计','2班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10012,'卫小宝',17,'女','福建','统计','2班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10013,'李绍',21,'女','福建','信计','2班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10014,'黄马华',22,'男','浙江','心理学','1班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10015,'艾蔚儿',19,'女','福建','计算机','1班','黎族');
commit;
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10016,'赵若辰',21,'男','江苏','心理学','1班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10017,'徐扬',22,'男','青海','计算机','1班','汉族');
insert into student (sid,sname,sage,ssex,snativeplace,smajor,sclass,snative) values (10018,'徐静静',19,'女','安徽','计算机','1班','黎族');
insert into course (cid,cname,cval,ctime,tid) values (2001,'数学',6,64,30001);
insert into course (cid,cname,cval,ctime,tid) values (2002,'英语',4,64,30002);
insert into course (cid,cname,cval,ctime,tid) values (2003,'体育',2,32,30003);
insert into course (cid,cname,cval,ctime,tid) values (2004,'马克思主义',6,64,30004);
insert into course (cid,cname,cval,ctime,tid) values (2005,'计算机基础',3,48,30005);
insert into course (cid,cname,cval,ctime,tid) values (2006,'心理学',4,48,30006);
insert into course (cid,cname,cval,ctime,tid) values (2007,'空间天气学',6,64,30007);
insert into teacher (tid,tname,tsex,tage,tlvl) values (30001,'马六','男',45,'高级教师');
insert into teacher (tid,tname,tsex,tage,tlvl) values (30002,'胡美丽','女',32,'中级教师');
insert into teacher (tid,tname,tsex,tage,tlvl) values (30003,'李强','男',40,'高级教师');
insert into teacher (tid,tname,tsex,tage,tlvl) values (30004,'胡适','男',55,'教授');
insert into teacher (tid,tname,tsex,tage,tlvl) values (30005,'钱枫','男',37,'高级教师');
insert into teacher (tid,tname,tsex,tage,tlvl) values (30006,'戴安安','女',27,'中级教师');
insert into teacher (tid,tname,tsex,tage,tlvl) values (30007,'张伯伦','男',47,'教授');
drop table teacher
create table teacher
(
  tid int,
  tname varchar2(100),
  tsex char(2),
  tage int,
  tlvl varchar2(100)
)

insert into mark (sid,cid,cmark) values (10001,2001,85);
insert into mark (sid,cid,cmark) values (10001,2002,75);
insert into mark (sid,cid,cmark) values (10001,2003,80);
insert into mark (sid,cid,cmark) values (10001,2004,70);
insert into mark (sid,cid,cmark) values (10001,2005,60);
insert into mark (sid,cid,cmark) values (10001,2006,95);
insert into mark (sid,cid,cmark) values (10001,2007,70);
insert into mark (sid,cid,cmark) values (10002,2001,80);
insert into mark (sid,cid,cmark) values (10002,2002,65);
insert into mark (sid,cid,cmark) values (10002,2003,70);
insert into mark (sid,cid,cmark) values (10002,2004,80);
insert into mark (sid,cid,cmark) values (10002,2005,55);
insert into mark (sid,cid,cmark) values (10002,2006,78);
insert into mark (sid,cid,cmark) values (10002,2007,82);
insert into mark (sid,cid,cmark) values (10003,2001,69);
insert into mark (sid,cid,cmark) values (10003,2002,57);
insert into mark (sid,cid,cmark) values (10003,2003,90);
insert into mark (sid,cid,cmark) values (10003,2004,80);
insert into mark (sid,cid,cmark) values (10003,2005,77);
insert into mark (sid,cid,cmark) values (10003,2006,92);
insert into mark (sid,cid,cmark) values (10003,2007,80);
insert into mark (sid,cid,cmark) values (10004,2001,85);
insert into mark (sid,cid,cmark) values (10004,2002,76);
insert into mark (sid,cid,cmark) values (10004,2003,66);
insert into mark (sid,cid,cmark) values (10004,2004,54);
insert into mark (sid,cid,cmark) values (10004,2005,80);
insert into mark (sid,cid,cmark) values (10004,2006,73);
insert into mark (sid,cid,cmark) values (10004,2007,80);
insert into mark (sid,cid,cmark) values (10005,2001,93);
insert into mark (sid,cid,cmark) values (10005,2002,82);
insert into mark (sid,cid,cmark) values (10005,2003,71);
insert into mark (sid,cid,cmark) values (10005,2004,68);
insert into mark (sid,cid,cmark) values (10005,2005,70);
insert into mark (sid,cid,cmark) values (10005,2006,86);
insert into mark (sid,cid,cmark) values (10005,2007,90);
insert into mark (sid,cid,cmark) values (10006,2001,69);
insert into mark (sid,cid,cmark) values (10006,2002,48);
insert into mark (sid,cid,cmark) values (10006,2003,90);
insert into mark (sid,cid,cmark) values (10006,2004,68);
insert into mark (sid,cid,cmark) values (10006,2005,80);
insert into mark (sid,cid,cmark) values (10006,2006,88);
insert into mark (sid,cid,cmark) values (10006,2007,70);
insert into mark (sid,cid,cmark) values (10007,2001,77);
insert into mark (sid,cid,cmark) values (10007,2002,75);
insert into mark (sid,cid,cmark) values (10007,2003,82);
insert into mark (sid,cid,cmark) values (10007,2004,67);
insert into mark (sid,cid,cmark) values (10007,2005,84);
insert into mark (sid,cid,cmark) values (10007,2006,95);
insert into mark (sid,cid,cmark) values (10007,2007,73);
insert into mark (sid,cid,cmark) values (10008,2001,97);
insert into mark (sid,cid,cmark) values (10008,2002,86);
insert into mark (sid,cid,cmark) values (10008,2003,68);
insert into mark (sid,cid,cmark) values (10008,2004,81);
insert into mark (sid,cid,cmark) values (10008,2005,71);
insert into mark (sid,cid,cmark) values (10008,2006,78);
insert into mark (sid,cid,cmark) values (10008,2007,64);
insert into mark (sid,cid,cmark) values (10009,2001,90);
insert into mark (sid,cid,cmark) values (10009,2002,75);
insert into mark (sid,cid,cmark) values (10009,2003,60);
insert into mark (sid,cid,cmark) values (10009,2004,57);
insert into mark (sid,cid,cmark) values (10009,2005,90);
insert into mark (sid,cid,cmark) values (10009,2006,85);
insert into mark (sid,cid,cmark) values (10009,2007,91);
insert into mark (sid,cid,cmark) values (10010,2001,85);
insert into mark (sid,cid,cmark) values (10010,2002,62);
insert into mark (sid,cid,cmark) values (10010,2003,72);
insert into mark (sid,cid,cmark) values (10010,2004,81);
insert into mark (sid,cid,cmark) values (10010,2005,91);
insert into mark (sid,cid,cmark) values (10010,2006,90);
insert into mark (sid,cid,cmark) values (10010,2007,66);
insert into mark (sid,cid,cmark) values (10011,2001,55);
insert into mark (sid,cid,cmark) values (10011,2002,75);
insert into mark (sid,cid,cmark) values (10011,2003,67);
insert into mark (sid,cid,cmark) values (10011,2004,87);
insert into mark (sid,cid,cmark) values (10011,2005,88);
insert into mark (sid,cid,cmark) values (10011,2006,77);
insert into mark (sid,cid,cmark) values (10011,2007,61);
insert into mark (sid,cid,cmark) values (10012,2001,77);
insert into mark (sid,cid,cmark) values (10012,2002,81);
insert into mark (sid,cid,cmark) values (10012,2003,91);
insert into mark (sid,cid,cmark) values (10012,2004,67);
insert into mark (sid,cid,cmark) values (10012,2005,60);
insert into mark (sid,cid,cmark) values (10012,2006,80);
insert into mark (sid,cid,cmark) values (10012,2007,74);
insert into mark (sid,cid,cmark) values (10013,2001,88);
insert into mark (sid,cid,cmark) values (10013,2002,75);
insert into mark (sid,cid,cmark) values (10013,2003,90);
insert into mark (sid,cid,cmark) values (10013,2004,60);
insert into mark (sid,cid,cmark) values (10013,2005,71);
insert into mark (sid,cid,cmark) values (10013,2006,95);
insert into mark (sid,cid,cmark) values (10013,2007,89);
insert into mark (sid,cid,cmark) values (10014,2001,65);
insert into mark (sid,cid,cmark) values (10014,2002,72);
insert into mark (sid,cid,cmark) values (10014,2003,68);
insert into mark (sid,cid,cmark) values (10014,2004,67);
insert into mark (sid,cid,cmark) values (10014,2005,60);
insert into mark (sid,cid,cmark) values (10014,2006,75);
insert into mark (sid,cid,cmark) values (10014,2007,81);
insert into mark (sid,cid,cmark) values (10015,2001,55);
insert into mark (sid,cid,cmark) values (10015,2002,67);
insert into mark (sid,cid,cmark) values (10015,2003,61);
insert into mark (sid,cid,cmark) values (10015,2004,71);
insert into mark (sid,cid,cmark) values (10015,2005,81);
insert into mark (sid,cid,cmark) values (10015,2006,88);
insert into mark (sid,cid,cmark) values (10015,2007,90);
insert into mark (sid,cid,cmark) values (10016,2001,72);
insert into mark (sid,cid,cmark) values (10016,2002,82);
insert into mark (sid,cid,cmark) values (10016,2003,92);
insert into mark (sid,cid,cmark) values (10016,2004,62);
insert into mark (sid,cid,cmark) values (10016,2005,63);
insert into mark (sid,cid,cmark) values (10016,2006,73);
insert into mark (sid,cid,cmark) values (10016,2007,83);
insert into mark (sid,cid,cmark) values (10017,2001,85);
insert into mark (sid,cid,cmark) values (10017,2002,77);
insert into mark (sid,cid,cmark) values (10017,2003,87);
insert into mark (sid,cid,cmark) values (10017,2004,79);
insert into mark (sid,cid,cmark) values (10017,2005,69);
insert into mark (sid,cid,cmark) values (10017,2006,58);
insert into mark (sid,cid,cmark) values (10017,2007,74);
insert into mark (sid,cid,cmark) values (10018,2001,88);
insert into mark (sid,cid,cmark) values (10018,2002,78);
insert into mark (sid,cid,cmark) values (10018,2003,88);
insert into mark (sid,cid,cmark) values (10018,2004,78);
insert into mark (sid,cid,cmark) values (10018,2005,68);
insert into mark (sid,cid,cmark) values (10018,2006,98);
insert into mark (sid,cid,cmark) values (10018,2007,78);
commit;

 二、题目

1.在学生表中找出人数至少是三个的地区

select snativeplace  from student group by snativeplace having count(*)>=3 /*having扫描的是每个小组*/

2.找出各地区女生年龄数目

select snativeplace,count(distinct sage) from student  where ssex='女' group by   snativeplace

3.找出各个地区女生的数学平均分

select snativeplace ,avg(cmark) from student,mark,course where student.sid=mark.sid and mark.cid=course.cid and ssex='女' and cname='数学'  
group by snativeplace  order by avg(cmark)

4.找出各个地区各门课的均分

select snativeplace ,cname,avg(cmark) from student s,mark sc,course c where s.sid=sc.sid and sc.cid=c.cid group by snativeplace ,c.cid,cname

5.找出低于所有人平均分的学生姓名

select sname from student where sid in(select sid from mark group by sid having avg(cmark)<(select avg(cmark)from mark))

6.找出年龄降序排序的3-6名学生信息

select * from(select * from( select * from student order by sage desc)where rownum<=7) order by sage 
select *from(
select * from(select * from( 
select * from student order by sage desc)where rownum<=7
) order by sage 
) where rownum<=5 order by sage desc

7.找出年龄最大学生

方法1：排序取第一条
select * from( select * from student order by sage desc) t where rownum=1
访法2：找到最大值，其次扫描那些记录的数值等于这个最大值
step1:select max(sage) from student
step2:select* from student where sage=(step1)
方法三：直接和原表的所有记录进行对比，大于等于他们所有记录则成立
select * from student where sage>=all(select sage from student)
方法4：排除法
select * from student where not sage<any(select sage from student)

8.找出均分最高的学生姓名

select*from(
select mark.sid,sname,avg(cmark) from mark,student where mark.sid=student.sid group by mark.sid,sname order by avg(cmark) desc ) 
where rownum=1
select * from student where sid in(select sid from mark  group by sid having avg(cmark)>=all(select avg(cmark) from mark group by sid))

9.找出均分最高的女生姓名

step1:select sid from student where ssex='女' /*找出女生学号*/
step2:select sid avg(cmark)amk from mark where sid in (step1)group by sid/*计算出女生均分表*/
step3:select sid from(step2)where amk>=all(select amk from step2)/*使用>=all的方式找到最高均分的学号*/
step4:select snme from student where sid in(step3)/*在学生表中兑换成姓名*/

10.找出数学成绩最高的学生姓名

step1: select sid from student where ssex='女'
step2: select cid from course where canme='数学'
step3: select * from mark where sid in(step1) and cid=(step2)
step4: select max(cmark) from (step3)
step5:select sid from (step3) where cmark =(step4)
step5:select sname from student where sid in(step5)