SQL语句题

SQL语句题

Student(Sno,Sname,Sage,Ssex)注释：学生表（学号，姓名，性别年龄，性别）

Course(Cno,Cname,Tno) 注释：课程表（课程号，课程名称，教师编号）

SC(Sno,Cno,score) 注释：成绩表（学号，课程号，成绩）

Teacher(Tno,Tname)注释：教师表（教师编号，教师名）

drop sequence  s_student;

create sequence s_student;

drop table student cascade constraint purge;

create table Student(

Sno number primary key,

Sname varchar(30),

Sage number(3),

Ssex char(1)

);

insert into Student values(s_student.nextval,'张三1',21,'m');

insert into Student values(s_student.nextval,'张三2',22,'m');

insert into Student values(s_student.nextval,'张三3',23,'w');

insert into Student values(s_student.nextval,'张三4',24,'m');

commit;

drop sequence  s_teacher;

create sequence s_teacher;

drop table teacher cascade constraint purge;

create table Teacher(

Tno number primary key,

Tname  varchar(30)

);

insert into teacher values(s_teacher.nextval,'里老师1');

insert into teacher values(s_teacher.nextval,'张三');

insert into teacher values(s_teacher.nextval,'里老师3');

insert into teacher values(s_teacher.nextval,'里老师4');

commit;

成绩

drop table sc cascade constraint purge;

create table SC(

Sno number constraint sc_sno_fk references student(sno),

Cno number constraint sc_cno_fk references course(cno),

score number,

constraint sc_sno_cno_pk primary key(sno,cno)

) ;

insert into sc values(1,2,58);

insert into sc values(2,4,21);

insert into sc values(3,3,76);

insert into sc values(4,1,50);

insert into sc values(2,1,66);

insert into sc values(1,3,20);

insert into sc values(2,2,30);

insert into sc values(3,2,50);

insert into sc values(4,4,55);

commit;

课程

drop sequence s_course;

create sequence s_course;

drop table course cascade constraint purge;

create table Course(

Cno number primary key,

Cname varchar(30),

Tno number constraint course_tno_fk references teacher(tno)

);

insert into course values(s_course.nextval,'java',1);

insert into course values(s_course.nextval,'javascript',2);

insert into course values(s_course.nextval,'jdbc',3);

insert into course values(s_course.nextval,'hibernate',4);

commit;

1、查询每个学生的学号，姓名，所修课程及成绩；

select * from student st join sc s on st.sno=s.sno join course co on co.cno=s.cno;

2、查询学过“001”或者学过编号“002”课程的同学的学号、姓名；

非关联子查询

select * from student where sno in (select sno from course where cno=2 or cno=1);

关联子查询

select * from student s where exist (select 1 from course c where s.sno=c.sno and (cno=1 or cno=2));

3、将课程号为“002”的授课老师改为“张三”；

update course set tno=(select tno  from teacher where tname='张三') where cno=4;

4、向SC表中插入一条记录，学号001，课程号003，成绩80；

delete from sc where sno=2 and cno=1;

5、删除“002”同学的“001”课程的成绩；

delete from sc where cno=1 and sno=4;

6、查询不及格的课程，并按课程号从大到小排列；

select score , cno  from  sc where score<60 order by cno desc;

7、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 score<60  group by sno having count(sno)>=2;

8、查询姓“李”的老师的姓名及授课情况；

select * from teacher t join course c on t.tno=c.tno where tname like '张%';

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序，若人数相同，按课程号升序排序；

select cno,count(cno) ,max(cname)

from(

select c.cno ,c.cname from sc s

join course c on s.cno=c.cno

)

group by cno

having count(cno)>1

order by cno desc;

10、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 cname||'[85-100]' name,score,c.cno

from sc s  join course c on s.cno=c.cno where score between 85 and 100

union

select cname||'[70-85]' name,score,c.cno

from sc s  join course c on s.cno=c.cno where score between 70 and 85

union

select cname||'[60-70]' name,score,c.cno

from sc s  join course c on s.cno=c.cno where score between 60 and 70

union

select cname||'[<60]' name,score,c.cno

from sc s  join course c on s.cno=c.cno where score<60