sql查询语句（教学）

[thslovehh]

关于教学数据库的三个基本表
学生 S(S#,SNAME,AGE,SEX)； 学习 SC(S#,C#,GRADE)； 课程 C(C#,CNAME,TEACHER)
(1)统计有学生选修的课程门数.


(2)求选修C4课程的学生的平均年龄.


(3)求LIU老师所授课程的每门课程的学生平均成绩.


(4)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.


(5)检索学号比WANG同学大,而年龄比他小的学生姓名.


(6)检索姓名以WANG打头的所有学生的姓名和年龄.


(7)在SC中检索成绩为空值的学生学号和课程号.


(8)求年龄大于女同学平均年龄的男学生姓名和年龄.

[jwdream2008]

1: select count (distinct C#)  From SC

[jwdream2008]

2: select Avg(age) from  S where S# in (select S# from SC where C#=C4)

[--小F--]

SQL语句练习题参考答案 
1、 select Sname,Ssex,Class from Student;
2、 select distinct depart from teacher;
3、 select Sno as '学号',Sname as '姓名',Ssex as '性别',Sbirthday as'出生日期',Class as'班号'from student;
或
select Sno as 学号,Sname as 姓名,Ssex as 性别,Sbirthday as 出生日期,Class as 班号 from student;
4、 select * from score where degree between 60 and 80;
或select * from score where degree>=60 and degree<=80;
5、 select * from score where degree in (85,86,88);
6、 select * from student where class='95031'or Ssex='女';
7、 select * from student order by class desc;
8、 select * from score order by cno asc ,degree desc;
或select * from score order by cno ,degree desc;
9、 select count(*) as CNT from student where class='95031';
10、select Sno as '学号',cno as '课程号', degree as '最高分' from score
where degree=(select max(degree) from score)
11、select avg(degree)as 课程平均分 from score where cno='3-105';
12、select cno,avg(degree) from score where cno like'3%'group by cno having   count(*) >5;
13、select Sno from score group by Sno having min(degree)>70 and max(degree)<90;
14、select student.Sname,score.Cno,score.degree from student,score where student.Sno=score.Sno;
15、select x.Sno,y.Cname,x.degree from score x,course y where x.Cno=y.Cno;
16、select x.Sname,y.Cname,z.degree from student x,course y,score z where x.Sno=z.Sno and z.Cno=y.Cno;
17、select y.Cno,avg(y.degree) from student x,score y where x.Sno=y.Sno and x.class='95033'group by y.cno;
18、select Sno,Cno,rank from score,grade where degree between low and upp order by rank;
19、select x.Cno,x.Sno,x.degree from score x,score y
where x.cno='3-105' and x.degree>y.degree and y.sno='109'and y.cno='3-105';
20、
1,查询成绩非本科最高 select *   from score b   where degree <(select max(degree) from score a where a.cno=b.cno);
2,查询成绩非本科最高并且选2门以上的学生的成绩:
21、select x.cno,x.Sno,x.degree from score x,score y where x.degree>y.degree and y.sno='109'and y.cno='3-105';
select cno,sno,degree from score   where degree >(select degree from score where sno='109' and cno='3-105')
22、select sno,sname,sbirthday from student where to_char(sbirthday,'yyyy')=(select to_char(sbirthday,'yyyy') from student where sno='108');
23、select cno,sno,degree from score where cno=(select x.cno from course x,teacher y where x.tno=y.tno and y.tname='张旭');
24、select tname from teacher where tno in(select x.tno from course x,score y where x.cno=y.cno group by x.tno having count(x.tno)>5);
25、select * from student where class in('95033','95031');
26、select distinct cno from score where degree in (select degree from score where degree>85);
27、select * from score where cno in(select x.cno from course x,teacher y where y.tno=x.tno and y.depart='计算机系');
28、select tname,prof from teacher where depart='计算机系' and prof not in (select prof from teacher where depart='电子工程系');
29、select * from score where cno='3-105' and degree>any (select degree from score where cno='3-245')order by degree desc;
30、select * from score where cno='3-105' and degree>all(select degree from score where cno='3-245');
31、select tname,tsex,tbirthday from teacher
union select sname,ssex,sbirthday from student;
32、select tname,tsex,tbirthday from teacher where tsex='女'
union select sname,ssex,sbirthday from student where ssex='女';
33、select * from score a where degree<(select avg(degree)
from score b where a.cno=b.cno);
34、select tname,depart from teacher a where exists
(select * from course b where a.tno=b.tno);
35、select tname,depart from teacher a where not exists
(select * from course b where a.tno=b.tno);
36、select class from student where ssex='男'group by class having count(*)>=2;
37、select * from student where sname not like'王_';
38、select sname as 姓名,(to_char(sysdate,'yyyy')-to_char(sbirthday,'yyyy')) as 年龄 from student
39、select sname,sbirthday as 最大 from student where   sbirthday =(select min (sbirthday) from student)
union select sname,sbirthday as 最小 from student where sbirthday =(select max(sbirthday) from student)  
40、select class,sname,sbirthday from student order by class desc,sbirthday;
41、select x.tname,y.cname from teacher x,course y where x.tno=y.tno and x.tsex='男';
42、select * from score where degree=(select max(degree)from score);
43、select sname from student where ssex=(select ssex from student where sname='李军');
44、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、select * from score where sno in(select sno from student where ssex='男') and cno=(select cno from course
where cname='计算机导论');

[黄_瓜]

引用楼主 thslovehh 的回复:

关于教学数据库的三个基本表
学生 S(S#,SNAME,AGE,SEX)； 学习 SC(S#,C#,GRADE)； 课程 C(C#,CNAME,TEACHER)
(1)统计有学生选修的课程门数.


(2)求选修C4课程的学生的平均年龄.


(3)求LIU老师所授课程的每门课程的学生平均成绩.


(4)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.


(5)检索学号比WANG同学大,而年龄比他小的学生姓名.


(6)检索姓名以WANG打头的所有学生的姓名和年龄.


(7)在SC中检索成绩为空值的学生学号和课程号.


(8)求年龄大于女同学平均年龄的男学生姓名和年龄.

兄台你杂光发帖不解贴呢

[thslovehh]

我也想解啊，问题是还没解出来啊，不敢随便解啊，各位都是高手、、、

[fspop]

结帖率：0.00%....

[thslovehh]

哥，我第一次发帖、、、