sql查询

 --学生表  S_id  S_name  S_age  S_sex
create table Student
(
  S_id varchar2(10),
  S_name varchar2(20),
  S_age date,
  S_sex varchar2(10)
)
 
insert into Student values('01' , '赵雷' , '01-1月-95' , '男');
insert into Student values('02' , '钱电' , '21-12月-96' , '男');
insert into Student values('03' , '孙风' , '20-5月-96' , '男'); 
insert into Student values('04' , '李云' , '06-8月-98' , '男'); 
insert into Student values('05' , '周梅' , '01-12月-95' , '女'); 
insert into Student values('06' , '吴兰' , '01-3月-95' , '女'); 
insert into Student values('07' , '郑竹' , '01-7月-97' , '女'); 
insert into Student values('08' , '王菊' , '20-1月-96' , '女');  
insert into Student values('09' , '王菊' , '20-1月-96' , '女');  


--课程表  C_id  C_name  T_id
create table Course
(
  C_id varchar2(10),
  C_name varchar2(20),
  T_id varchar2(10)
)
 
insert into Course values('01' , 'JAVA' , '01'); 
insert into Course values('02' , 'HTML' , '02'); 
insert into Course values('03' , 'Oracle' , '03');  


--教师表  T_id  T_name
create table Teacher
(
  T_id varchar2(10),
  T_name varchar2(20)
) 


insert into Teacher values('01' , '张三'); 
insert into Teacher values('02' , '李四'); 
insert into Teacher values('03' , '王五');  


--选课表  S_id  S_id  score
create table SC
(
  S_id varchar2(10),
  C_id varchar2(10),
  score number(20)
) 


insert into SC values('01' , '01' , 80); 
insert into SC values('01' , '02' , 90); 
insert into SC values('01' , '03' , 99); 
insert into SC values('02' , '01' , 70); 
insert into SC values('02' , '02' , 60); 
insert into SC values('02' , '03' , 80); 
insert into SC values('03' , '01' , 80); 
insert into SC values('03' , '02' , 80); 
insert into SC values('03' , '03' , 80); 
insert into SC values('04' , '01' , 50); 
insert into SC values('04' , '02' , 30); 
insert into SC values('04' , '03' , 20);
insert into SC values('05' , '01' , 76); 
insert into SC values('05' , '02' , 87); 
insert into SC values('06' , '01' , 31); 
insert into SC values('06' , '03' , 34); 
insert into SC values('07' , '02' , 89); 
insert into SC values('07' , '03' , 98);

--完成下列查询需求:
--1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数
select s.*,a1.score as 课程01的分数,a2.score as 课程02的分数
from student s,sc a1,sc a2
where s.s_id=a1.s_id and s.s_id=a2.s_id and a1.c_id=01 and a2.c_id=02 and a1.score>a2.score;


--2、查询"01"课程比"02"课程成绩低的学生的信息及课程分数
select s.*,a1.score as 课程01的分数,a2.score as 课程02的分数
from student s,sc a1,sc a2
where s.s_id=a1.s_id and s.s_id=a2.s_id and a1.c_id=01 and a2.c_id=02 and a1.score<a2.score;
--3、查询平均成绩大于等于60分的同学的学生编号、学生姓名和平均成绩
select s.s_id,s.s_name,trunc(avg(score)) 平均成绩
from student s,sc a
where s.s_id=a.s_id 
group by s.s_id,s.s_name HAVING trunc(avg(score))>=60;


--4、查询平均成绩小于60分的同学的学生编号、学生姓名和平均成绩
select s.s_id,s.s_name,trunc(avg(score)) 平均成绩
from student s,sc a
where s.s_id=a.s_id 
group by s.s_id,s.s_name HAVING trunc(avg(score))<60;


--5、查询所有同学的、学生姓名、选课总数、所有课程的总成绩
select s.s_id 学生编号,s.s_name 学生姓名,count(a.c_id) 选课总数,sum(score)
from student s,sc a
where s.s_id=a.s_id 
group by s.s_id,s.s_name 
order by s.s_id;


--6、查询"李"姓老师的数量
select count(t_id)
from teacher
where t_name like '李%';


--7、查询学过"张三"老师所授课程的同学的信息
select s.*
from student s,sc a,teacher t,course c
where s.s_id=a.s_id and a.c_id=c.c_id and c.t_id=t.t_id and t_name='张三'
order by s.s_id;


--8、查询没学过"张三"老师所授课程的同学的信息
select *
from student
where s_id not in(
select student.s_id
from student,sc,teacher,course
where student.s_id=sc.s_id and sc.c_id=course.c_id and course.t_id=teacher.t_id and t_name='张三')
order by s_id;


--9、查询学过编号为"01"并且也学过编号为"02"的课程的同学的信息
select distinct s.*
from student s,sc a1,sc a2
where s.s_id=a1.s_id and s.s_id=a2.s_id and a1.c_id=01 and a2.c_id=02;


--10、查询学过编号为"01"但是没有学过编号为"02"的课程的同学的信息
select student.*
from student,sc
where student.s_id=sc.s_id and sc.c_id=01 and student.s_id not in(
select distinct s.s_id
from student s,sc a
where s.s_id=a.s_id and a.c_id=02
);


--11、查询没有学全所有课程的同学的信息
select student.*
from student
where student.s_id not in(select sc.s_id
  from sc
  group by sc.s_id HAVING count(sc.c_id)=(select count(course.c_id) from course)
)
group by student.s_id,student.s_name,student.s_age,student.s_sex
order by student.s_id;


--12、查询至少有一门课与学号为"01"的同学所学的课程相同的同学的信息   
select distinct student.*
from student,sc
where student.s_id=sc.s_id and sc.c_id in (select c_id from sc where s_id='01')
group by student.s_id,student.s_name,student.s_age,student.s_sex，sc.c_id
order by student.s_id;


--13、查询和学号为"01"的同学学习的课程完全相同的其他同学的信息   
select distinct s.s_id,s.s_name,s.s_age,s.s_sex
from student s ,sc
where s.s_id in(
      select distinct sc.s_id
      from sc
      where sc.c_id in(select distinct sc.c_id from sc where s_id='01')
      group by sc.s_id
      having count(sc.c_id)=(select count(sc.c_id) from sc where s_id='01')
) and sc.s_id=s.s_id 
group by s.s_id,s.s_name,s.s_age,s.s_sex 
having count(sc.s_id)=(select count(sc.c_id) from sc where sc.s_id='01');


--14、查询没学过"张三"老师讲授的任何一门课程的学生的信息
select distinct s.*
from student s
where s_id not in(
  select sc.s_id
  from course，teacher,sc
  where course.t_id=teacher.t_id and sc.c_id=course.c_id and t_name='张三'
)
order by s.s_id;


--15、查询两门及其以上课程不及格的同学的学号，姓名及其平均成绩
select s.s_id,s.s_name,trunc(avg(sc.score))
from student s,sc
where s.s_id=sc.s_id and sc.s_id in(
  select s_id
  from sc
  where score<60
  group by s_id HAVING count(c_id)>=2
)
group by  s.s_id,s.s_name
order by s_id;


--16、检索"01"课程分数小于60分的同学的信息，结果按分数降序排列
select s.*,sc.score
from sc,student s
where sc.s_id=s.s_id and sc.score<60 and sc.c_id='01'
order by sc.score desc;


--17、按平均成绩从高到低显示所有学生的所有课程的成绩以及平均成绩
select st.s_id,sc1.score 课程01,sc2.score 课程02,sc3.score 课程03,avg(s.score) as 平均成绩
from student st
left join sc s on(st.s_id=s.s_id)
left join sc sc1 on(s.s_id=sc1.s_id) and sc1.c_id=01
left join sc sc2 on(s.s_id=sc2.s_id) and sc2.c_id=02
left join sc sc3 on(s.s_id=sc3.s_id) and sc3.c_id=03
group by st.s_id,sc1.score,sc2.score,sc3.score
order by avg(s.score) desc;




--18、查询各科成绩最高分、最低分和平均分，及格率，中等率，优良率，优秀率：以如下形式显示：
--课程ID，课程name，最高分，最低分，平均分，及格率，中等率，优良率，优秀率--及格为>=60，中等为：-80，优良为：-90，优秀为：>=90
select c.c_id 课程ID,c.c_name 课程name,max(score) 最高分,min(score) 最低分,trunc(avg(score),2) 平均分, 
  trunc(count(case when score between 90 and 100 then '90-100' else null end)/count(sc.s_id),2) "优秀率",
  trunc(count(case when score between 80 and 89 then '80-89' else null end)/count(sc.s_id),2) "优良率",
  trunc(count(case when score between 60 and 79 then '60_79' else null end)/count(sc.s_id),2) "中等率",
  trunc(count(case when score >60 then '60_100' else null end)/count(sc.s_id),2) "及格率",
  trunc(count(case when score <60 then '60_0' else null end)/count(sc.s_id),2) "不及格率"
from sc,course c
where sc.c_id=c.c_id 
group by c.c_id,c.c_name
order by c.c_id;


insert into tb_sc(s_id,c_id)
values(10,02);


--20、查询学生的总成绩并进行排名
select s.s_id,s.s_name,sum(score) 总成绩
from student s
left join sc on(sc.s_id=s.s_id)
group by s.s_id,s.s_name
order by sum(score) desc;


--21、查询不同老师所教不同课程的平均分，查询结果从高到低显示
select t.t_id,t.t_name,trunc(avg(sc.score)) as 所教课程的平均分
from sc,course c,teacher t
where c.c_id=sc.c_id and t.t_id=c.t_id
group by t.t_id,t.t_name
order by t.t_id;


--22、查询选修"张三"老师所授课程的学生中，成绩最高的学生信息及其成绩（最高分可能不止一个）
select student.*,sc.score 
from sc,student,teacher,course c 
where teacher.t_id=c.t_id and c.c_id=sc.c_id and sc.s_id=student.s_id 
      and teacher.t_name='张兆亿'
      and sc.score=(select max(score)from sc where sc.c_id=c.c_id) 
 
--23、统计各科成绩各分数段人数：课程编号,课程名称,100-85,85-70,70-60,0-60及所占百分比
select sc.c_id as 课程编号, c.c_name as 课程名称,
  count(case when score between 85 and 100 then '85-100' else null end) "100-85",
  trunc(count(case when score between 85 and 100 then '85-100' else null end)/count(sc.s_id),2) "所占百分比",
  count(case when score between 70 and 84 then '70-85' else null end) "85-70",
  trunc(count(case when score between 70 and 84 then '70-85' else null end)/count(sc.s_id),2) "所占百分比",
  count(case when score between 60 and 69 then '60_70' else null end) "70-60",
  trunc(count(case when score between 60 and 69 then '60_70' else null end)/count(sc.s_id),2) "所占百分比",
  count(case when score<60 then '60_0' else null end) "60 -0",
  trunc(count(case when score <60 then '60_0' else null end)/count(sc.s_id),2) "所占百分比"
from sc,course c
where sc.c_id=c.c_id
group by sc.c_id,c.c_name;


--24、查询选修了全部课程的学生信息
select *
from student             
where s_id IN
   (select s_id from SC
    group by s_id    --根据Sno分组，统计每个学生选修了几门课程。如果等于course的总数，就是我们要找的Sno
    having count(*) = (select count(*) from course )
    )    --统计course中共有几门课程




--25、查询各科成绩前三名的记录,显示结果为：学生编号、学生姓名、课程名称、成绩
select s.s_id 学生编号,s.s_name 学生姓名,c.c_name 课程名称,pm.score 成绩
from (select s_id,c_id,score,row_number() 
      over(partition by c_id order by score desc) rn
      from sc
      ) pm,student s,course c
where pm.s_id=s.s_id and pm.c_id=c.c_id and rn <= 3
order by c.c_name;


--26、查询每门课程被选修的学生数
select sc.c_id ,count(sc.s_id) 学生人数
from sc,student 
where sc.s_id=student.s_id 
group by sc.c_id 


--27、查询出只选修了两门课程的全部学生的学号和姓名
select s.s_id,s.s_name,count(sc.c_id) 所选课程数
from student s,sc
where s.s_id=sc.s_id 
group by s.s_id,s.s_name
having count(sc.c_id)=2;


--28、查询男生、女生人数
select count(s1.s_id) 男生人数,count(s2.s_id) 女生人数
from student s
left join student s1 on(s.s_id=s1.s_id) and s1.s_sex='男'
left join student s2 on(s.s_id=s2.s_id) and s2.s_sex='女'


--29、查询名字中含有"风"字的学生信息
select *
from student
where s_name like '%风%';


--30、查询同名同性学生名单，并统计人数,显示的结果为：学生姓名、性别、人数
select s_name,s_sex,count(*)
from student 
group by s_name,s_sex
having count(*)>1


--31、查询1990-01-20出生的学生名单(注：Student表中Sage列的类型是datetime) 
select *
from student
where s_age='1-1月-95';


--32、查询每门课程的平均成绩，结果按平均成绩降序排列，平均成绩相同时，按课程编号升序排列
select c_id 课程编号,avg(score) 平均成绩
from sc
group by c_id
order by avg(score) desc,c_id asc;


--33、查询平均成绩大于等于85分的所有学生的学号、姓名和平均成绩
select s.s_id 学号,s.s_name 姓名,avg(sc.score)
from student s,sc
where s.s_id=sc.s_id 
group by  s.s_id,s.s_name
having avg(sc.score)>85;


--34、查询课程名称为"数学"，且分数低于60分的学生姓名和分数
select s.s_name,sc.score
from student s,sc
where sc.s_id=s.s_id and c_id in(
      select c_id
      from course
      where c_name='HTML'   
      ) and sc.score<60;


--35、查询所有学生的课程及分数情况
select sc.*,c.c_name
from sc,course c
where sc.c_id=c.c_id;


--36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数
select s.s_name,c.c_name,sc.score
from student s,sc,course c
where s.s_id=sc.s_id and sc.c_id=c.c_id and sc.score>=70;


--37、查询不及格的学生信息
select s.*,sc.score
from student s,sc
where s.s_id=sc.s_id and sc.score<60;


--38、查询课程编号为01且课程成绩在80分以上的学生的学号和姓名
select s.s_id,s.s_name
from student s,sc
where s.s_id=sc.s_id and sc.c_id=01 and sc.score>=80;


--39、求每门课程的学生人数
select sc.c_id,count(s.s_id)
from sc,student s
where sc.s_id=s.s_id
group by sc.c_id;
 
--40、查询各学生的年龄
select s.s_id,s.s_name,to_char(sysdate,'YYYY')-to_char(s.s_age,'YYYY')  年龄
from student s;


--41、查询本周过生日的学生
select s.s_id,s.s_name
from student s
where to_char(s.s_age,'day')=to_char(sysdate,'day');


--42、查询本月过生日的学生
select s.s_id,s.s_name
from student s
where to_char(s.s_age,'MM')=to_char(sysdate,'MM');