-- 练习

--1、 查询Student表中的所有记录的Sname、Ssex和Class列。
select SNAME,SSEX,CLASS FROM STUDENT;

--2、 查询教师所有的单位即不重复的Depart列。
-- distinct:去除重复   all:显示所有(默认)
select distinct DEPART from TEACHER;
select DEPART from TEACHER group by DEPART;

--3、 查询Student表的所有记录。
select * from STUDENT;

--4、 查询Score表中成绩在60到80之间的所有记录。
select * from SCORE where DEGREE>=60 AND DEGREE<=80;
SELECT * FROM SCORE WHERE DEGREE BETWEEN 60 AND 80;

--5、 查询Score表中成绩为85，86或88的记录。
select * from SCORE where degree in ('85','86','88','123');

--6、 查询Student表中“95031”班或性别为“女”的同学记录。
select * from STUDENT where CLASS ='95031' or SSEX='女';

--7、 以Class降序查询Student表的所有记录。
select * from STUDENT order by CLASS desc;

--8、 以Cno升序、Degree降序查询Score表的所有记录。
select * from SCORE order by CNO asc,DEGREE desc;

--9、 查询“95031”班的学生人数。
select count(sno) from STUDENT where CLASS='95031';

--10、查询Score表中的最高分的学生学号和课程号。
select SNO,CNO from SCORE where degree=(select max(degree) from score);

--11、查询‘3-105’号课程的平均分。
select avg(degree) from SCORE where CNO='3-105';

--12、查询Score表中至少有5名学生选修的并以3开头的课程的平均分数。
select CNO, avg(degree) from SCORE where CNO like '3%' group by CNO having count(CNO)>4;

select * from score order by sno; 

--13、查询最低分大于70 ，最高分小于90 的Sno 列。  ==>
select SNO from SCORE where degree between 70 and 90;
select sno,max(degree),min(degree) from score group by sno having max(degree)<90 and min(degree)>70

--14、查询所有学生的Sname、Cno和Degree列。
-- join:默认inner join 内连接
select sname,cno,degree from score inner join student on student.sno=score.sno;

--15、查询所有学生的Sno、Cname和Degree列。
select SNO,CNAME,DEGREE from SCORE join COURSE on COURSE.CNO=SCORE.CNO;

--16、查询所有学生的Sname、Cname和Degree列。
SELECT STUDENT.SNAME,CNAME,DEGREE FROM STUDENT join SCORE on STUDENT.SNO=SCORE.SNO join COURSE on COURSE.CNO=SCORE.CNO;
 
--17、查询“95033”班所选课程的平均分。

select avg(degree) from score where sno in (select sno from student where class='95033');               
select avg(degree) from score,student where student.sno=score.sno and class='95033';

--18、假设使用如下命令建立了一个grade表：
create table grade(low   NUMERIC(3,0),upp   NUMERIC(3,0),rank   char(1));
insert into grade values(90,100,'A');
insert into grade values(80,89,'B');
insert into grade values(70,79,'C');
insert into grade values(60,69,'D');
insert into grade values(0,59,'E');
commit;

select * from grade;
现查询所有同学的Sno、Cno和rank列。
select sno,cno,rank,score.degree from grade join score on score.degree between low and upp; 

--19、查询选修“3-105”课程的成绩高于“109”号同学成绩的所有同学的记录。

select * from score where cno='3-105' and degree>any(
select degree from score where sno=109)

select * from student,score where score.cno='3-105' and student.sno=score.sno and score.degree>(
select degree from SCORE where cno='3-105' and sno='109');

select * from score,student where student.sno=score.sno and score.cno='3-105' and score.degree>(select degree from SCORE where cno='3-105' and sno='109');

--20、查询score中选学一门以上课程的同学中分数为非最高分成绩的记录。

select * from score s1,(select sno,max(degree) ma from score group by sno having count(1)>1) s2 where s1.sno=s2.sno and s1.degree!=s2.ma

select * from score;

insert into score values('103','3-166',88);

select * from score a where degree <(
select max(degree) from score b where a.cno=b.cno) and sno in(
select sno from score group by sno having count(*)>1
);

select * from score;

--21、查询成绩高于学号为“109”、课程号为“3-105”的成绩的所有记录。
select * from student,score where student.sno=score.sno and score.degree>all(select degree from score where sno='109') ;

--22、查询和学号为108的同学同年出生的所有学生的Sno、Sname和Sbirthday列。
select sno,sname,sbirthday from student where to_char(sbirthday,'yyyy')=(select to_char(sbirthday,'yyyy') from student where sno='108');

--23、查询“张旭“教师任课的学生成绩。
select degree from score where cno in (select cno from course where tno in(select tno from teacher where tname='张旭'));

--24、查询选修某课程的同学人数多于5人的教师姓名。
select tname from teacher where teacher.tno=(
select tno from course where course.cno=(
select cno from score group by cno having count(*)>5));

--25、查询95033班和95031班全体学生的记录。
select * from student where class='95033' or class='95031' order by class;

--26、查询存在有85分以上成绩的课程Cno
select  distinct cno from score where degree>85;

select * from score;

--27、查询出“计算机系“教师所教课程的成绩表。
select * from score join course on course.cno=score.cno join teacher on teacher.tno=course.tno where teacher.depart='计算机系';

--28、查询“计算机系”与“电子工程系“不同职称的教师的Tname和Prof。
select * from teacher;
select tname,prof from teacher where prof not in (select prof from teacher where depart ='电子工程系' and prof in (
select prof from teacher where depart='计算机系')) and depart in ('计算机系','电子工程系');

--29、查询选修编号为“3-105“课程且成绩至少高于选修编号为“3-245”的同学的Cno、Sno和Degree,并按Degree从高到低次序排序。
select cno,sno,degree from score where cno='3-105' and degree>(select min(degree) from score where cno='3-245') order by degree desc;

--30、查询选修编号为“3-105”且成绩高于选修编号为“3-245”课程的同学的Cno、Sno和Degree.
select * from score where cno='3-105' and degree>(select max(degree) from score where cno='3-245');

--31、查询所有教师和同学的name、sex和birthday.
select tname,tsex,tbirthday from teacher union select sname,ssex,sbirthday from student;

--32、查询所有“女”教师和“女”同学的name、sex和birthday.
select tname,tsex,tbirthday from teacher where tsex='女' union select sname,ssex,sbirthday from student where ssex='女';

--33、查询成绩比该课程平均成绩低的同学的成绩表。

select * from score s1,(select cno,avg(degree)ma from score group by cno) s2 where s1.cno=s2.cno and s1.degree<s2.ma

select * from score a where a.degree<(select avg(degree) from score b where a.cno=b.cno group by cno);

--34、查询所有任课教师的Tname和Depart.
select tname,depart from teacher where tno in(select tno from course where cno in(select cno from score));

--35  查询所有未讲课的教师的Tname和Depart. 
select tname,depart from teacher where tno not in(select tno from course where cno in(select cno from score));

--36、查询至少有2 名男生的班号。
select class from student where ssex='男'group by class having count(*)>=2;

--37、查询Student表中不姓“王”的同学记录。
select * from student where sname not like '王%';

--38、查询Student表中每个学生的姓名和年龄。
select sname,(to_char(sysdate,'yyyy')-to_char(sbirthday,'yyyy')) from student;

--39、查询Student表中最大和最小的Sbirthday日期值。
select max(sbirthday),min(sbirthday) from student;

--40、以班号和年龄从大到小的顺序查询Student表中的全部记录。
select * from student order by class desc,to_char(sysdate,'yyyy')-to_char(sbirthday,'yyyy') desc;

--41、查询“男”教师及其所上的课程。
select cname,tsex from course join teacher on course.tno=teacher.tno where tsex='男';

--42、查询最高分同学的Sno、Cno和Degree列。
select sno,cno,degree from score where degree=(select max(degree) from score);

--43、查询和“李军”同性别的所有同学的Sname.
select sname from student where ssex=(select ssex from student where sname='李军');

--44、查询和“李军”同性别并同班的同学Sname.
select sname from student where ssex=(select ssex from student where sname='李军') and class=(select class from student where sname='李军');

--45、查询所有选修“计算机导论”课程的“男”同学的成绩表
select * from score where sno in(select sno from student where ssex='男') and cno in(select cno from course where cname='计算机导论') ;