Oracle表管理实验

一、创建如下表

学生表：student

字段名称    字段类型        约束       

sno                     varchar2(10)             主键

sname                varchar2(20)

sage                    number(2)

ssex                    varchar2(5)

教师表：teacher

tno                      varchar2(10)             主键

tname                varchar2(20)

课程表：course

cno                     varchar2(10)             与tno联合做主键

cname               varchar2(20)

tno                      varchar2(20)

成绩表：sc

sno                     varchar2(10)             与cno联合做主键

cno                     varchar2(10)

score                  number(4,2)

create table student(
sno varchar2(10) primary key,
sname varchar2(20),
sage varchar2(20),
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) ，
primary key(cno,tno)
)


create table sc(
sno varchar2(10)，
cno varchar2(10),
score number(4,2),
primary key(sno,cno)
)

二、为各表输入数据

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;

insert into teacher values ('t001', '刘阳');
insert into teacher values ('t002', '谌燕');
insert into teacher values ('t003', '胡明星');
commit;

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;

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;

三、按下列要求完成查询

1、查询每门课程被选修的学生数。

SELECT cno,COUNT(sno) 
FROM sc 
GROUP BY cno;

2、查询出只选修了一门课程的全部学生的学号和姓名。

SELECT sno,sname
FROM  student 
WHERE sno in(
SELECT sno
FROM  sc
GROUP by sno
HAVING COUNT(cno)=1
);

3、查询男生、女生人数。

SELECT count(ssex) as 男生人数 FROM student WHERE ssex='男';
SELECT count(ssex) as 女生人数 FROM student WHERE ssex='女';

4、查询姓“张”的学生名单。

SELECT * FROM student WHERE sname LIKE '张%';

5、查询同名同姓学生名单，并统计同名人数。

SELECT sname,count(*) as NUM 
FROM student
GROUP BY sname 
HAVING COUNT(*)>1

6、1981 年出生的学生名单。

7、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 c.cname,c.cno,AVG(sc.score) 
FROM course c,sc 
WHERE c.cno = sc.cno
GROUP BY c.cname,c.cno
ORDER BY AVG(sc.score) DESC,c.cno ASC;

8、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 s.sno,s.sname,AVG(score) 
FROM student s,sc 
WHERE s.sno=sc.sno 
GROUP BY s.sno,s.sname 
HAVING AVG(score)>85;

9、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。

SELECT cno,COUNT(*) 
FROM sc 
GROUP BY cno
HAVING COUNT(*)>10
ORDER BY COUNT(*) DESC,cno;

10、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 as 课程ID,MAX(score) as 最高分,min(score) as 最低分 
FROM sc 
GROUP BY cno;

11、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 c.cno,c.cname,round(avg(sc.score),2) avg ,round(
(SELECT COUNT(*) 
FROM sc WHERE cno = c.cno and score>=60)/(
SELECT COUNT(*) 
FROM sc 
WHERE cno= c.cno
)*100,2)||'%' AS path_rate 
FROM course c,sc 
WHERE c.cno = sc.cno 
GROUP BY c.cname,c.cno 
ORDER BY avg, path_rate DESC;

12、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 c.cno AS 课程ID,c.cname AS 课程名,
SUM(CASE
WHEN sc.score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) 
AS "[100-85]",
SUM(CASE
WHEN sc.score BETWEEN 70 AND 84 THEN 1 ELSE 0 END) 
AS "[84-70]",
SUM(CASE
WHEN sc.score BETWEEN 60 AND 69 THEN 1 ELSE 0 END) 
AS "[69-60]",
SUM(CASE
WHEN sc.score BETWEEN 0 AND 59 THEN 1 ELSE 0 END) 
AS "[<60]"
FROM course c,sc 
WHERE c.cno = sc.cno 
GROUP BY c.cno,c.cname;