数据库 基础学习6— 查询 练习题

--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。

--select COUNT(*) from Teacher group by Depart
select distinct Depart from  Teacher

--3、 查询Student表的所有记录。
select *from Student
select Sno,Sname,Ssex,Sbirthday,Class 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 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) 

--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(class) from Student group by Class having Class='95031'
select COUNT(*) from student where class='95031'--优

--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 * from Score where Degree=(select MAX(Degree) from Score)
select top 1 *from Score order by Degree desc

--11、 查询每门课的平均成绩。
select Cno,AVG(Degree) 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 Cno,AVG(Degree) from Score group by cno having (COUNT(*)>5) and (cno like '3%')


--13、查询分数大于70，小于90的Sno列。
select Sno from Score where Degree>70 and Degree<90
select Sno from Score where Degree between 70 and 90--包含临界值

--14、查询所有学生的Sname、Cno和Degree列。
select Sname,Cno,Degree,Class from Student,Score where Student.Sno=Score.Sno


--15、查询所有学生的Sno、Cname和Degree列。
select Sno,Cname,Degree from Course,Score where Course.Cno=Score.Cno


--16、查询所有学生的Sname、Cname和Degree列。
select Sname,Cname,Degree from Student join score on Student.Sno=Score.Sno join  Course on Course.Cno=Score.Cno

--17、 查询“95033”班学生的平均分。
select cno,avg(Degree) from Student,Score where (Student.Sno=Score.Sno) and (Student.Class='95033') group by Score.Cno

select avg(Degree)  from Student,Score where (Student.Sno=Score.Sno) and (Student.Class='95033')


--18、 假设使用如下命令建立了一个grade表：现查询所有同学的Sno、Cno和rank列。
(select Sno,Cno,rank from Score,grade where  (Score.Degree between 90 and 100)and grade.rank='A')
union 
(select Sno,Cno,rank from Score,grade where  (Score.Degree between 80 and 89)and grade.rank='B')
union
(select Sno,Cno,rank from Score,grade where  (Score.Degree between 70 and 79)and grade.rank='C')
union 
(select Sno,Cno,rank from Score,grade where  (Score.Degree between 60 and 69)and grade.rank='D')
union 
(select Sno,Cno,rank from Score,grade where  (Score.Degree between 0 and 59)and grade.rank='E')

select Sno,Cno,rank from Score,grade where  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
select * from Score where Cno='3-105' and Degree>(select degree from Score where Sno='109'and Cno='3-105')
--select * from Score where (degree>(select Degree from Score where Sno=109)) in (Cno='3-105')

--20、查询score中选学多门课程的同学,这些同学中分数为非最高分成绩的记录。----
select * from score where degree not in (select MAX(Degree) from Score where  Sno  in (select Sno from Score group by sno having COUNT(*)>1 )) and (Sno in (select sno from Score 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 Sno,Sname,Sbirthday from Student s1 where (YEAR(s1.Sbirthday) in
(select YEAR(s2.Sbirthday) from Student s2 where Sno='108' ))and(Sno!='108')


--23、查询“张旭“教师任课的学生成绩。
select *from Score s3 where s3.Cno=(select Cno from Course s2 where s2.Tno=(select Tno from Teacher s1 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 s1 where Tno in (select Tno from Course s2 where cno in (select Cno from Score group by Cno having COUNT(*)>5))
--select Tname from (Teacher join Course on Teacher.Tno=Course.Tno join Score on Course.Cno=Score.Cno) group by score.Cno having count(*)>5


--25、查询95033班和95031班全体学生的记录。
select *from Student where Class in (95033,95031)

select * from Teacher  join Course on Course.Tno=Teacher.Tno join  Score on Course.Cno=Score.Cno join (select *from Student where Class in (95033,95031)) s1 on Score.Sno=s1.Sno


--26、  查询存在有85分以上成绩的课程Cno.
select * from Score
select cno from Score group by Cno having MAX(Degree)>85--分组

select distinct Cno from Score where Degree>85--distinct消除重复行

--27、查询出“计算机系“教师所教课程的成绩表。
select * 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
select Tname,Prof from Teacher s1 where Depart='计算机系' and not exists(select Prof from Teacher s2 where Depart='电子工程系' and s1.Prof=s2.Prof)--加上and 条件目的就是让前面的一记录一条一条的判定，而不是等着前面的条件执行完了，再跟后面的判断！
union
select Tname,Prof from Teacher s1 where Depart='电子工程系' and not exists(select Prof from Teacher s2 where Depart='计算机系' and s1.Prof=s2.Prof)--exists 意思 就是（）里只要返回数据就是真！不返回数据 空表就false！


--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 >any (select Degree from Score where Cno='3-245')
select Cno,Sno,Degree from Score where Cno='3-105' and Degree >(select min(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 
select Cno,Sno,Degree from Score where Cno='3-105' and Degree >(select max(Degree) from Score where Cno='3-245')
select Cno,Sno,Degree 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 Tname 'name',Tsex 'sex',Tbirthday 'birthday' 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 'name',Tsex 'sex',Tbirthday 'birthday' 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 where Degree <( select AVG(Degree) from Score s2 group by Cno having s1.Cno=s2.Cno )---相关子查询
 
--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 group by Cno))



--35 、 查询所有未讲课的教师的Tname和Depart. 
select Tname from Teacher where Tno in( select Tno from Course where Cno not in ( select Cno from Score group by Cno))


--36、查询至少有2名男生的班号。
select s1.Class from (select Class from Student where Ssex='男') s1 group by s1.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,(YEAR(GETDATE())-YEAR(Sbirthday)) '年龄'  from student 


--39、查询Student表中最大和最小的Sbirthday日期值。
select MAX(Sbirthday) from student 
union
select 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 Sno,sname,ssex,class,(YEAR(GETDATE())-YEAR(Sbirthday)) '年龄'  from student order by Class desc ,年龄 desc



--41、查询“男”教师及其所上的课程。
select * from  Course,Teacher where Teacher.Tno=Course.Tno and  Teacher.Tsex='男'

--42、查询最高分同学的Sno、Cno和Degree列。
select *from Score
select Sno,Cno,Degree from Score where Degree=(select MAX(Degree) from Score) 

--查询总成绩最高分的
select Sno,Cno,Degree from Score where sno in
(select top 1 Sno  from Score group by Sno order by SUM(Degree) desc)

--43、查询和“李军”同性别的所有同学的Sname.
select * from Student 
select Sname from Student where Ssex =(select Ssex from Student where Sname='李军') and (Sname!='李军')


--44、查询和“李军”同性别并同班的同学Sname.
select Sname from Student where Class=(select Class from Student where Sname='李军') and Ssex =(select Ssex from Student where Sname='李军')and(Sname!='李军')

--相关子查询--关键是分析出哪个是关键点
select * from Student 
select Class,sname from student s1 where ssex=(select class,sname,ssex from student s2 where sname='李军' and s2.class= s1.class)

--45、查询所有选修“计算机导论”课程的“男”同学的成绩表。
select Degree from Score where 
cno=(select Cno from course s1 where Cname='计算机导论') and( Sno in (select Sno from Student where Ssex='男'))