一、創建表並初始化數據
1、表說明
student(學生表)、teacher(教師表)、course(課程表)、sc(分數表)
2、創建表
//學生表
create table student( sno varchar2(10) primary key, sname varchar2(20), sage number(2), ssex varchar2(5) );
//教師表 create table teacher( tno varchar2(10) primary key, tname varchar2(20) );
//課程表 create table course( cno varchar2(10), cname varchar2(20), tno varchar2(20), constraint pk_course primary key (cno,tno) );
//分數表 create table sc( sno varchar2(10), cno varchar2(10), score number(4,2), constraint pk_sc primary key (sno,cno) );
3、插入初始化數據
/*******初始化學生表的數據******/
insert into student values ('s001','張三',23,'男');
insert into student values ('s002','李四',23,'男');
insert into student values ('s003','吳鵬',25,'男');
insert into student values ('s004','琴沁',20,'女');
insert into student values ('s005','王麗',20,'女');
insert into student values ('s006','李波',21,'男');
insert into student values ('s007','劉玉',21,'男');
insert into student values ('s008','蕭蓉',21,'女');
insert into student values ('s009','陳蕭曉',23,'女');
insert into student values ('s010','陳美',22,'女');
commit;
/******************初始化教師表***********************/
insert into teacher values ('t001', '劉陽');
insert into teacher values ('t002', '諶燕');
insert into teacher values ('t003', '胡明星');
commit;
/***************初始化課程表****************************/
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;
/***************初始化成績表***********************/
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;
二、SQL語句
1、查詢“c001”課程比“c002”課程成績高的所有學生的學號；
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;
或
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、查詢平均成績大於60 分的同學的學號和平均成績；
select sno,avg(score) from sc group by sno having avg(score)>60;
******************************************************************
3、查詢所有同學的學號、姓名、選課數、總成績；
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、查詢姓“劉”的老師的個數；
select count(*) from teacher where tname like '劉%';
******************************************************************
5、查詢沒學過“諶燕”老師課的同學的學號、姓名；
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='諶燕') t
where c.tno=t.tno
) b
where s.cno = b.cno
)
或
select * 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='諶燕'
)
******************************************************************
6、查詢學過“c001”並且也學過編號“c002”課程的同學的學號、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、查詢學過“諶燕”老師所教的所有課的同學的學號、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='諶燕'
******************************************************************
8、查詢課程編號“c002”的成績比課程編號“c001”課程低的所有同學的學號、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、查詢所有課程成績小於60 分的同學的學號、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、查詢沒有學全所有課的同學的學號、姓名；
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)
或
select * from student where sno in
(
select sno from
(
select stu.sno,c.cno from student stu cross join course c minus select sno,cno from sc
)
)
******************************************************************
11、查詢至少有一門課與學號為“s001”的同學所學相同的同學的學號和姓名；
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、查詢至少學過學號為“s001”同學所有一門課的其他同學學號和姓名；
select * from sc
left join student st on st.sno=sc.sno
where sc.sno<>'s001'
and sc.cno in (select cno from sc where sno='s001')
******************************************************************
13、把“SC”表中“諶燕”老師教的課的成績都更改為此課程的平均成績；
update sc c set score=
(
select avg(c.score) from course a,teacher b
where a.tno=b.tno and b.tname='諶燕' 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='諶燕')
******************************************************************
14、查詢和“s001”號的同學學習的課程完全相同的其他同學學號和姓名；
select* from sc where sno<>'s001'
minus
( select* from sc minus select * from sc where sno='s001')
******************************************************************
15、刪除學習“諶燕”老師課的SC 表記錄；
delete from sc where sc.cno in
(
select cno from course c
left join teacher t on c.tno=t.tno
where t.tname='諶燕'
)
******************************************************************
16、向SC 表中插入一些記錄，這些記錄要求符合以下條件：沒有上過編號“c002”課程的同學學號、“c002”號課的平均成績；
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、查詢各科成績最高和最低的分：以如下形式顯示：課程ID，最高分，最低分
select cno ,max(score),min(score) from sc group by cno;
******************************************************************
18、按各科平均成績從低到高和及格率的百分數從高到低順序
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、查詢不同老師所教不同課程平均分從高到低顯示
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、統計列印各科成績,各分數段人數:課程ID,課程名稱,[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、查詢各科成績前三名的記錄:(不考慮成績並列情況)
select * from
(select sno,cno,score,row_number()over(partition by cno order by score desc) rn from sc)
where rn<4
******************************************************************
22、查詢每門課程被選修的學生數
select cno,count(sno)from sc group by cno;
******************************************************************
23、查詢出只選修了一門課程的全部學生的學號和姓名
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、查詢男生、女生人數
select ssex,count(*)from student group by ssex;
******************************************************************
25、查詢姓“張”的學生名單
select * from student where sname like '張%';
******************************************************************
26、查詢同名同性學生名單，並統計同名人數
select sname,count(*)from student group by sname having count(*)>1;
******************************************************************
27、1981 年出生的學生名單(注：Student 表中Sage 列的類型是number)
select sno,sname,sage,ssex from student t where to_char(sysdate,'yyyy')-sage =1988
******************************************************************
28、查詢每門課程的平均成績，結果按平均成績升序排列，平均成績相同時，按課程號降序排列
select cno,avg(score) from sc group by cno order by avg(score)asc,cno desc;
******************************************************************
29、查詢平均成績大於85 的所有學生的學號、姓名和平均成績
select st.sno,st.sname,avg(score) from student st
left join sc on sc.sno=st.sno
group by st.sno,st.sname having avg(score)>85;
******************************************************************
30、查詢課程名稱為“數據庫”，且分數低於60 的學生姓名和分數
select sname,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、查詢所有學生的選課情況；
select st.sno,st.sname,c.cname from student st,sc,course c
where sc.sno=st.sno and sc.cno=c.cno;
******************************************************************
32、查詢任何一門課程成績在70 分以上的姓名、課程名稱和分數；
select st.sname,c.cname,sc.score from student st,sc,course c
where sc.sno=st.sno and sc.cno=c.cno and sc.score>70
******************************************************************
33、查詢不及格的課程，並按課程號從大到小排列
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、查詢課程編號為c001 且課程成績在80 分以上的學生的學號和姓名；
select st.sno,st.sname,sc.score from sc,student st
where sc.sno=st.sno and cno='c001' and score>80;
******************************************************************
35、求選了課程的學生人數
select count(distinct sno) from sc;
******************************************************************
36、查詢選修“諶燕”老師所授課程的學生中，成績最高的學生姓名及其成績
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='諶燕' and sc.score=
(select max(score)from sc where sc.cno=c.cno)
******************************************************************
37、查詢各個課程及相應的選修人數
select cno,count(sno) from sc group by cno;
******************************************************************
38、查詢不同課程成績相同的學生的學號、課程號、學生成績
select a.* from sc a ,sc b where a.score=b.score and a.cno<>b.cno
******************************************************************
39、查詢每門功課成績最好的前兩名
select * from (
select sno,cno,score,row_number()over(partition by cno order by score desc) my_rn from sc t
)
where my_rn<=2
******************************************************************
40、統計每門課程的學生選修人數（超過10 人的課程才統計）。要求輸出課程號和選修人數，查詢結果按人數降序排列，若人數相同，按課程號升序排列
select cno,count(sno) from sc
group by cno having count(sno)>10
order by count(sno) desc,cno asc;
******************************************************************
41、檢索至少選修兩門課程的學生學號
select sno from sc group by sno having count(cno)>1;
或
select sno from sc group by sno having count(sno)>1;
******************************************************************
42、查詢全部學生都選修的課程的課程號和課程名
select distinct(c.cno),c.cname from course c ,sc where sc.cno=c.cno
或
select cno,cname from course c where c.cno in (select cno from sc group by cno)
******************************************************************
43、查詢沒學過“諶燕”老師講授的任一門課程的學生姓名
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='諶燕')
******************************************************************
44、查詢兩門以上不及格課程的同學的學號及其平均成績
select sno,avg(score)from sc
where sno in
(
select sno from sc where sc.score<60
group by sno having count(sno)>1
) group by sno
******************************************************************
45、檢索“c004”課程分數小於60，按分數降序排列的同學學號
select sno from sc where cno='c004' and score<90 order by score desc;
******************************************************************
46、刪除“s002”同學的“c001”課程的成績
delete from sc where sno='s002' and cno='c001';