sql语句相关子查询例题解析

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" and class = 95031

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(*) from student where class=’95031’

10、查询Score表中的最高分的学生学号和课程号。（子查询或者排序）

Select sno,cno from score order by degree desc limit 0,1

Select sno,cno from score where degree=(select max(degree) from score)

查询语句查询出一个或者一列结果，可以作为其他查询语句的参数来使用，这就是子查询，也就是查询的嵌套

11、查询每门课的平均成绩（要按照课程分组 group by，然后求每门课平均分）。//avg

Select avg(degree) ,cno from score group by cno

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 avg(degree) from score where cno like "3%" group by cno having count(*)>=5

--查询以3开头的课程信息--模糊查询

Select * from score where cno like “3%”

--查询选修课程人数大于等于5的课程编号

--select cno from score group by cno having count(*)>=5

13、查询分数大于70，小于90的Sno列。

Select sno from score where degree>70 and degree<90

14、查询所有学生的Sname、Cno和Degree列。

Select ( select sname from student where student.sno=score.sno),cno,degree from score

//select *from a,b 笛卡尔积

Select sname,cno,degree from score join student on score.sno=student.sno

15、查询所有学生的Sno、Cname和Degree列。

Select sno,degree,(select cname from course where course.cno=score.cno) from score

16、查询所有学生的Sname、Cname和Degree列。

select (Select sname from student where student.sno=score.sno),(select cname from course where course.cno=score.cno),degree from score

或者

Select sname,cname,degree from student,course,score where student.sno =score.sno and course.cno = score.cno

17、查询“95033”班学生的平均分。

Select avg(degree),cno from score join student on student.sno= score.sno

where cno in (select cno from score where class=95033) group by cno

18、假设使用如下命令建立了一个grade表：

create table grade(low int(3),upp int(3),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’)

现查询所有同学的Sno、Cno和rank列。

Select sno,cno,rank from score join grade on degree between low and upp

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

Select * from score where cno = "3-105" and degree > (Select degree from score where sno = 109 and cno = "3-105")

20、查询score中选学多门课程的同学中分数为非最高分成绩的记录。

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

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

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 * from student where year(sbirthday) = (select year(sbirthday) from student where sno = 108)

23、查询“张旭“教师任课的学生成绩。

select * 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 tno in (select tno from course where cno in (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

26、查询存在有85分以上成绩的课程Cno.

Select cno from score where degree > 85

27、查询出“计算机系”教师所教课程的成绩表。

select degree from score where cno in (select cno from course join teacher on course.tno = teacher.tno where depart = "计算机系")

或者

select degree from score where cno in (select cno from course where tno in (Select tno from teacher where 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 where prof not in (select prof from teacher where prof in (select prof from teacher where depart = "计算机系") and depart = "电子工程系" )

Union

Select * from teacher where prof not in (select prof from teacher where prof in (select prof from teacher where depart = "电子工程系") and depart = "计算机系" )

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 * from score where cno = "3-105" and degree > any( select degree from score where cno = "3-245")

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 > all( select degree from score where cno = "3-245")

31、查询所有教师和同学的name、sex和birthday.

Select sname,ssex,sbirthday from student union select tname,tsex,tbirthday from teacher

32、查询所有“女”教师和“女”同学的name、sex和birthday.

Select sname,ssex,sbirthday from student where ssex = "女" union select tname,tsex,tbirthday from teacher where tsex = "女"

33、查询成绩比该课程平均成绩低的同学的成绩表。

select sno,cno,degree from score a where degree < (Select avg(degree) from score b where a.cno = b.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 distinct 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 distinct Cno from Score))

36、查询至少有2名男生的班号。

Select class from student group by class having count(ssex = "男") > 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,year(now())-year(sbirthday) 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,year(now())-year(sbirthday) desc

或者

select * from Student order by class desc,Sbirthday

41、查询“男”教师及其所上的课程。

select cname from course join teacher on teacher.tno = course.tno where tsex = "男"

或者

Select cname from course where tno in (Select tno from teacher 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)

或者

Select * from score order by degree desc limit 0,1

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")

&& 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 student.sno,sname,cname,degree from score,student,course where score.sno = student.sno and course.cno = score.cno and ssex = "男" and cname= "计算机导论"

或者

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‘)

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热心网友时间：2022-04-09 00:19

什么问题？
http://blog.csdn.net/asciil/article/details/5176924
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