oracle作业题

​
---oracle作业题
create table student(
 sno varchar2(10) primary key,
 sname varchar2(20),
 sage number(2),
 ssex varchar2(5)
 );
 create table teacher(
 tno varchar2(10) primary key,
 tname varchar2(20)
 );
 create table course(
 cno varchar2(10),
 cname varchar2(20),
 tno varchar2(20),
 constraint pk_course primary key (cno,tno)
 );
 create table sc(
 sno varchar2(10),
 cno varchar2(10),
 score number(4,2),
 constraint pk_sc primary key (sno,cno)
 );
 ----------------------
  /*******初始化学生表的数据******/
insert into student values ('s001','张三',23,'男');
insert into student values ('s002','李四',23,'男');
insert into student values ('s003','吴鹏',25,'男');
insert into student values ('s004','琴沁',20,'女');
insert into student values ('s005','王丽',20,'女');
insert into student values ('s006','李波',21,'男');
insert into student values ('s007','刘玉',21,'男');
insert into student values ('s008','萧蓉',21,'女');
insert into student values ('s009','陈萧晓',23,'女');
insert into student values ('s010','陈美',22,'女');
commit;

------------------------------
/******************初始化教师表***********************/
insert into teacher values ('t001', '刘阳');
insert into teacher values ('t002', '谌燕');
insert into teacher values ('t003', '胡明星');
commit;
 /***************初始化课程表****************************/
insert into course values ('c001','J2SE','t002');
 insert into course values ('c002','Java Web','t002');
 insert into course values ('c003','SSH','t001');
 insert into course values ('c004','Oracle','t001');
 insert into course values ('c005','SQL SERVER 2005','t003');
 insert into course values ('c006','C#','t003');
 insert into course values ('c007','JavaScript','t002');
 insert into course values ('c008','DIV+CSS','t001');
 insert into course values ('c009','PHP','t003');
 insert into course values ('c010','EJB3.0','t002');
 commit;
 ----------------------------
  /***************初始化成绩表***********************/
insert into sc values ('s001','c001',78.9);
 insert into sc values ('s002','c001',80.9);
 insert into sc values ('s003','c001',81.9);
 insert into sc values ('s004','c001',60.9);
 insert into sc values ('s001','c002',82.9);
 insert into sc values ('s002','c002',72.9);
 insert into sc values ('s003','c002',81.9);
 insert into sc values ('s001','c003','59');
 commit;
 
 -----------------------------------------------------------
 ---1、查询“c001”课程比“c002”课程成绩高的所有学生的学号;
 ---a,b是临时表
select a.* from
 (select * from sc a where a.cno='c001') a,
 (select * from sc b where b.cno='c002') b
 where a.sno=b.sno and a.score > b.score;
 
 ---------
  select * from sc a
 where a.cno='c001'
 and  exists(select * from sc b where b.cno='c002' and a.score>b.score
 and a.sno = b.sno);
 ----2、查询平均成绩大于60 分的同学的学号和平均成绩;
 ----思路:先将avg(score)>60的同学按sno分组,再查询学号和平均成绩
 
 select sno,avg(score) from sc  group by sno having avg(score)>60;
 
--- 3、查询所有同学的学号、姓名、选课数、总成绩; 
---a,s时临时表 
---先从sc表按照sno分组,查询sno,总成绩,总课程数,查到的结果作为临时表a
----student表作为临时表s
 select a.*,s.sname 
 from (select sno,sum(score),count(cno) from sc group by sno) a ,student s 
 where a.sno=s.sno;
 
----4、查询姓“刘”的老师的个数;
select count(*)  from TEACHER where TNAME like '刘%';
 
----5、查询没学过“谌燕”老师课的同学的学号、姓名;
  /*法一  select a.sno,a.sname from student a
 where a.sno
 not in
 (select distinct s.sno
  from sc s,
       (select c.*
        from course c ,
            (select tno
             from teacher t
             where tname='谌燕')t
        where c.tno=t.tno) b
   where s.cno = b.cno );*/
 
 select sno,sname from student st 
 where st.sno not in
 (select distinct sno from sc s join course c on s.cno=c.cno
 join teacher t on c.tno=t.tno where tname='谌燕');
 
 -------------------------------------------------------------------
 
 ----6、查询学过“c001”并且也学过编号“c002”课程的同学的学号、姓名;
  select st.* from sc a
 join sc b on a.sno=b.sno
 join student st on st.sno=a.sno
 where a.cno='c001' and b.cno='c002' and st.sno=a.sno;
 
---7、查询学过“谌燕”老师所教的所有课的同学的学号、姓名;
 select st.* from student st join sc s on st.sno=s.sno
 join course c on s.cno=c.cno
 join teacher t on c.tno=t.tno
 where t.tname='谌燕'; 
 
----8、查询课程编号“c002”的成绩比课程编号“c001”课程低的所有同学的学号、姓名;
select * from student st
 join sc a on st.sno=a.sno
 join sc b on st.sno=b.sno
 where a.cno='c002' and b.cno='c001' and a.score < b.score 
 
------9、查询所有课程成绩小于60 分的同学的学号、姓名; 
select st.*,s.score from student st
 join sc s on st.sno=s.sno
 join course c on s.cno=c.cno
 where s.score <60; 
 ---------------------------------
 ----10、查询没有学全所有课的同学的学号、姓名;
---左连接student与sc,限定条件stu.sno=sc.sno
---按照学号,姓名分组,限定cno<课程总数
 select stu.sno,stu.sname,count(sc.cno) from student stu
 left join sc on stu.sno=sc.sno
 group by stu.sno,stu.sname
 having count(sc.cno)<(select count(distinct cno)from course);
 -----------------------
----11、查询至少有一门课与学号为“s001”的同学所学相同的同学的学号和姓名;
 select st.* from student st,
 (select distinct a.sno from
 (select * from sc) a,
 (select * from sc where sc.sno='s001') b
 where a.cno=b.cno) h
 where st.sno=h.sno and st.sno<>'s001'

---12、查询至少学过学号为“s001”同学所有一门课的其他同学学号和姓名;

select * from sc left join student st
on st.sno=sc.sno
where sc.sno <> 's001'
   and sc.sno in (select cno from sc where sno='s001');

----13、把“SC”表中“谌燕”老师教的课的成绩都更改为此课程的平均成绩;

update sc c set 
score=(select avg(c.score) from course a,teacher b 
       where a.tno=b.tno and b.tname='谌燕' and a.cno=c.cno
       group by c.cno)
where cno in(select cno from course a, teacher b
              where a.tno=b.tno and b.tname='谌燕');
-------------------------------------------------------------------------
----14、查询和“s001”号的同学学习的课程完全相同的其他同学学号和姓名;              
select* from sc where sno<>'s001'
 minus
 (
 select* from sc
 minus
 select * from sc where sno='s001'
 )
-----------15、删除学习“谌燕”老师课的SC 表记录;
delete from sc
 where in (select sc.cno
           from course c
           left join teacher t
             on c.tno = t.tno
            and t.tname = '谌燕'
         
         );


-----16、向SC 表中插入一些记录,
----这些记录要求符合以下条件:没有上过编号“c002”课程的同学学号、“c002”号课的平均成绩;                   

 insert into sc
   (sno, cno, score)
   select distinct st.sno,
                   sc.cno,
                   (select avg(score) from sc where cno = 'c002')
     from student st, sc
    where not exists (select *
             from sc
            where cno = 'c002'
              and sc.sno = st.sno)
      and sc.cno = 'c002';

-----17、查询各科成绩最高和最低的分:以如下形式显示:课程ID,最高分,最低分      
select cno,  max(score), min(score) from sc group by cno;

-----18、按各科平均成绩从低到高和及格率的百分数从高到低顺序
select cno,
       avg(score),
       sum(case
             when score >= 60 then
              1
             else
              0
           end) / count(*) as 及格率
  from sc
 group by cno
 order by avg(score), 及格率 desc;
 
----19、查询不同老师所教不同课程平均分从高到低显示 
select max(t.tno),max(t.tname),max(c.cno),max(c.cname),c.cno,avg(score) from sc , course c,teacher t
 where sc.cno=c.cno and c.tno=t.tno
 group by c.cno
 order by avg(score) desc
----20、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[ <60] 
select sc.cno,c.cname,
 sum(case  when score between 85 and 100 then 1 else 0 end) AS "[100-85]",
 sum(case  when score between 70 and 85 then 1 else 0 end)  AS "[85-70]",
 sum(case  when score between 60 and 70 then 1 else 0 end) AS "[70-60]",
 sum(case  when score <60 then 1 else 0 end) AS "[<60]"
 from sc, course c
 where  sc.cno=c.cno
 group by sc.cno ,c.cname;
--- 21、查询各科成绩前三名的记录:(不考虑成绩并列情况)
select *
  from (select sno,
               cno,
               score,
               row_number() over(partition by cno order by score desc)  rn
          from sc)
 where rn < 4;
-----22、查询每门课程被选修的学生数
 select cno,count(sno) from sc group by cno;
 
----23、查询出只选修了一门课程的全部学生的学号和姓名

select sc.sno, st.sname, count(cno)
  from student st
  left join sc
    on sc.sno = st.sno
 group by st.sname, sc.sno
having count(cno) = 1;

----24、查询男生、女生人数
select ssex,count(ssex) from student group by ssex;
----25、查询姓“张”的学生名单
select * from student where sname like '张%';

---26、查询同名同性学生名单,并统计同名人数
 select sname,count(*)from student group by sname having count(*)>1;
 
 ---27、1996 年出生的学生名单(注:Student 表中Sage 列的类型是number)
 select sno,sname,sage,ssex from student  where to_char(sysdate,'yyyy')-sage =1996
 

 ---28、查询每门课程的平均成绩,结果按平均成绩升序排列,平均成绩相同时,按课程号降序排列

  select cno,avg(score) from sc group by cno order by avg(score)asc,cno desc;

---29、查询平均成绩大于85 的所有学生的学号、姓名和平均成绩
select  st.sno,st.sname,avg(sc.score)  from student st  join sc 
on st.sno=sc.sno
group by st.sno,st.sname having avg(sc.score)>85;


---30、查询课程名称为“数据库”,且分数低于60 的学生姓名和分数
 select st.sname,sc.score from student st , sc ,course c
 where st.sno=sc.sno
   and sc.cno=c.cno 
   and c.cname='Oracle' 
   and sc.score < 60;
 
 ---31、查询所有学生的选课情况;
 select  st.sno,st.sname,sc.cno, c.cname   from student st , sc ,course c
where st.sno=sc.sno and sc.cno=c.cno;
 

 
---32、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 st.sname,c.cname,sc.score from student st,sc,course c
where st.sno=sc.sno and sc.cno=c.cno and sc.score > 70;



 
---33、查询不及格的课程,并按课程号从大到小排列


 select sc.sno,c.cname,sc.score from sc,course c
 where sc.cno=c.cno and sc.score<60 order by sc.cno desc;

34、查询课程编号为c001 且课程成绩在80 分以上的学生的学号和姓名;

select  st.sno,st.sname,sc.score from student st, sc
where st.sno=sc.sno and sc.cno='c001' and sc.score > 80;


 

35、求选了课程的学生人数
----distinct 去除重复的行
 select count(distinct sno) from sc;

 36、查询选修“谌燕”老师所授课程的学生中,成绩最高的学生姓名及其成绩
/* select  st.sname,sc.score   from student st,sc,course c,teacher t
 where st.sno=sc.sno and sc.cno=c.cno and c.tno=t.tno 
   and t.tname='谌燕'and sc.score in
   (
     select max(sc.score)  from sc where sc.cno=c.cno
   );
*/   
 select st.sname,score from student st,sc ,course c,teacher t
 where st.sno=sc.sno and sc.cno=c.cno and c.tno=t.tno 
   and t.tname='谌燕' and sc.score =
   (
      select max(score)from sc where sc.cno=c.cno
   );  
 

 
 
 
37、查询各个课程及相应的选修人数

select cno,count(sno) from sc group by cno;


38、查询不同课程成绩相同的学生的学号、课程号、学生成绩
---不同课程
---成绩相同
select    a.* from sc a,sc b
where a.score=b.score and a.cno != b.cno;


select a.* from sc a ,sc b 
where a.score=b.score and a.cno<>b.cno;

39、查询每门功课成绩最好的前两名

----row_number的用途非常广泛,排序最好用它,
----它会为查询出来的每一行记录生成一个序号,
----依次排序且不会重复,
----注意使用row_number函数时必须要用over子句选择对某一列进行排序才能生成序号。

---row_number() over()分组排序功能
---在使用 row_number() over()函数时候,
---over()里头的分组以及排序的执行晚于 where group by  order by 的执行

---partition by 用于给结果集分组,
---如果没有指定那么它把整个结果集作为一个分组,
---它和聚合函数不同的地方在于它能够返回一个分组中的多条记录,
---而聚合函数一般只有一个反映统计值的记录
select * from
   (
        ---row_number() over()分组排序
        ---自定义my_rn为排序列 
        ---partition by cno 按cno分组
        ---order by score desc按score降序排序
        select sno,
                cno,
                score,
                row_number() over(partition by cno order by score desc) my_rn
          from sc t
    )
 ----my_rn <= 2限定排名为前两名   
 where my_rn <= 2;



---40、统计每门课程的学生选修人数(超过10 人的课程才统计)。
---要求输出课程号和选修人数,查询结果按人数降序排列,若人数相同,按课程号升序排列
 

----group by cno having count(sno)>10
----按cno分组,HAVING短语筛选分组,选择超过10人的cno分组
----order by count(sno) desc,cno asc
----先按人数降序排序,再按课程号升序排序
----多个列属性进行排序时,排序的顺序是,从左到右,依次排序
select cno,count(sno) from sc 
group by cno having count(sno)>10
 order by count(sno) desc,cno asc;




41、检索至少选修两门课程的学生学号



 select sno from sc 
 group by sno having count(cno)>=2;
 ---先按学生分组,再筛选 选修课程数>=2 的分组



42、查询全部学生都选修的课程的课程号和课程名

----根据sc.cno+c.cname去除重复
----distinct同时作用在了sc.cno和c.cname上
select distinct  sc.cno,c.cname   
from sc , course c
where sc.cno=c.cno


----嵌套查询
----先查询sc表中的所有cno,
----再根据cno查询course表中对应的cname

 select cno,cname from course c
 where c.cno in
 (
    select cno from sc group by cno
    ---按cno分组查询所有的cno
 )

43、查询没学过“谌燕”老师讲授的任一门课程的学生姓名


     
 ---先查询学过“谌燕”老师讲授的任一门课程的学生学号sno
 ---再查询学生表中  学号sno不在这个范围内  的学生姓名sname
      
 select st.sname
   from student st
  where st.sno not in (select distinct sc.sno
                         from sc, course c, teacher t
                        where sc.cno = c.cno
                          and c.tno = t.tno
                          and t.tname = '谌燕'
                       )



44、查询两门以上不及格课程的同学的学号及其平均成绩
----先查询成绩<60的学生的学号sno,并按sno分组,筛选挂科数大于2的分组
----再根据成绩<60的学生的学号sno,查询其平均成绩

 select sno, avg(score)
   from sc
  where sno in (select sno
                  from sc
                 where sc.score < 60
                 group by sno
                having count(cno) >2)
  group by sno

45、检索“c002”课程分数小于90,按分数降序排列的同学学号

 select sno from sc where cno='c002' and score<90 order by score desc;


46、删除“s002”同学的“c001”课程的成绩

  delete from sc where sno='s002' and cno='c001';
  
  

​

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转载自blog.csdn.net/ThinkPet/article/details/81432873