oracle从入门到精通 之 三.SQL基础的练习题目（用心总结版）

/*Student(Sno,Sname,Sage,Ssex) 学生表   
Course(Cno,Cname,Tno) 课程表   
SC(Sno,Cno,score) 成绩表   
Teacher(Tno,Tname) 教师表 
*/
 
--学生表结构
create table student(
sno varchar2(10) , 
sname varchar2(20), 
sage number(2), 
ssex varchar2(5), 
primary key(sno)
) 
  
--教师表结构 
create table teacher( 
tno varchar2(10) primary key, 
tname varchar2(20) 
) 
 
--课程表结构
create table course( 
cno varchar2(10), 
cname varchar2(20), 
tno varchar2(20), 
constraint pk_course primary key (cno) ,
constraint fk_course foreign key(tno)
references teacher(tno) 
on delete cascade
) 
--成绩表
create table sc( 
scno  varchar2(10),
sno varchar2(10), 
cno varchar2(10), 
score number(4,2), 
constraint pk_sc primary key (scno),
constraint fk_sno foreign key(sno)
references student(sno)
on delete cascade,
constraint fk_cno foreign key(cno)
references course(cno)
on delete cascade
) 
 
--初始化数据
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');

select * from student

commit
--插入教师数据
insert into teacher values ('t001', '刘阳');

insert into teacher values ('t002', '谌燕');

insert into teacher values ('t003', '胡明星');
commit;
select * from teacher

--插入课程数据
 
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;
select * from course

--成绩表插入数据
insert into sc values ('sc001', 's001', 'c001', 78.9);

insert into sc values ('sc002', 's002', 'c001', 80.9);

insert into sc values ('sc003', 's003', 'c001', 81.9);

insert into sc values ('sc004', 's004', 'c001', 60.9);

insert into sc values ('sc005', 's001', 'c002', 82.9);

insert into sc values ('sc006', 's002', 'c002', 72.9);

insert into sc values ('sc007', 's003', 'c002', 81.9);

insert into sc values ('sc008', 's001', 'c003', '59');
commit;

select * from sc

--写出SQL语句
 
1、查询“c001”课程比“c002”课程成绩高的所有学生的学号；  
---自连接
 select s1.sno
   from sc s1
   join sc s2
     on s1.SNO = s2.sno
    and s1.cno = 'c001'
    and s2.cno = 'c002'
    and s1.score > s2.score

2、查询平均成绩大于70分的同学的学号和平均成绩； 

select avg(score), sno from sc group by sno having avg(score) > '70'
 
3、查询所有同学的学号、姓名、选课数、总成绩；
--gorp by中不能出现分组函数  
select student.sno, student.sname, count(sc.cno), sum(sc.score)
  from student
  left join sc
    on student.sno = sc.sno
 group by student.sno, student.sname
order by student.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； 

 

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 c.sname, a.*, b.cno, b.score
  from （select *
  from sc
 where sc.cno = 'c001' ）a, （select * from sc
 where sc.cno = 'c002' ）b, student c
 where a.sno = b.sno
   and a.sno = c.sno
 
7、查询学过“谌燕”老师所教的所有课的同学的学号、姓名；   
--第一种方法
select distinct s.*
  from sc,
       student s,
       (select c.*
          from course c, teacher t
         where c.tno = t.tno
           and t.tname = '谌燕') yc
 where sc.cno = yc.cno
   and sc.sno = s.sno
   order by s.sno
--第二种方法
select distinct 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；   
 --或看成三表连接 同第一题
select s.*, b.cno, b.score, a.cno, a.score
  from student s, （select *
  from sc
 where sc.cno = 'c001') a, （select * from sc
 where sc.cno = 'c002') b
 where a.score > b.score
   and a.sno = s.sno

9、查询所有课程成绩小于60分的同学的学号、姓名； 
select s.*,sc.score,sc.cno,c.cname
  from student s, sc,course c
 where s.sno = sc.sno
 and c.cno =sc.cno
   and sc.score < '60'
  
10、查询没有学全所有课的同学的学号、姓名； 
方法一： 
--注意allc未出现在group by中
select stu.sno, stu.sname, count(sc.cno) ,（select count(distinct cno) from course）as allc
  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)

方法二：
--cross join 全连接  minus去同存异返回左边表的差集
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；  
--自己写的
   select distinct s.*
     from student s, sc
    where s.sno = sc.sno
      and sc.cno in (select sc.cno from sc where sc.sno = 's001')
         and sc.sno <> 's001'
--网上看的
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.cno 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 cno in (select cno
                 from course a, teacher b
                where a.tno = b.tno
                  and b.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(*)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、1981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 t where to_char(sysdate,'yyyy')-sage =1988

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(score)
  from student st
  left join sc
    on sc.sno = st.sno
 group by st.sno, st.sname
having avg(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 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、查询所有学生的选课情况；  
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 sc.sno = st.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 sc, student st
 where sc.sno = st.sno
   and cno = 'c001'
   and score > 80;

35、求选了课程的学生人数  
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,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  
select a.* from sc a ,sc b where a.score=b.score and a.cno<>b.cno
 
39、查询每门功成绩最好的前两名  
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、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(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)>1; 
 
42、查询全部学生都选修的课程的课程号和课程名  
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、查询没学过“谌燕”老师讲授的任一门课程的学生姓名  
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='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  
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、检索“c004”课程分数小于60，按分数降序排列的同学学号  
select sno from sc where cno='c004' 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';