---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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