sql语句小练习一

create database aaa

go

use aaa

go

create table student(

   sno varchar(3),

sname varchar(4) not null,--性别

ssex varchar(2) not null,--出生年月

sbirthday datetime,--所在班级

class varchar(5)

)

go

 

create table teacher(

tno varchar(3) not null primary key,--教工姓名

tname varchar(4) not null,--教工性别

tsex varchar(2) not null,--教工出生日期

tbirthday datetime,--职称

prof varchar(6),--所在部门

depart varchar(10)

 

)

go

 

create table course

(

--课程号

cno varchar(5) not null primary key,--课程名称

cname varchar(10) not null,--教工编号

tno varchar(3) 

 

)

go

 

create table score

(

--学号

sno varchar(3),--课程号

cno varchar(5),--成绩

degree decimal(4,1)

)

go

insert into student values('108','曾华','男','1977-09-01','95033')

insert into student values('105','匡明','男','1975-10-02','95031')

insert into student values('107','王丽','女','1976-01-23','95033')

insert into student values('101','李军','男','1976-02-20','95033')

insert into student values('109','王芳','女','1975-02-10','95031')

insert into student values('103','陆君','男','1974-06-03','95031')

insert into teacher values('804','李诚','男','1958-12-02','副教授','计算机系')

insert into teacher values('856','张旭','男','1969-03-12','讲师','电子工程系')

insert into teacher values('825','王萍','女','1972-05-05','助教','计算机系')

insert into teacher values('831','刘冰','女','1958-08-14','助教','电子工程系')

insert into course values('3-105','计算机导论','825')

insert into course values('3-245','操作系统','804')

insert into course values('6-166','数字电路','856')

insert into course values('9-888','高等数学','831')

insert into score values('103','3-245','86')

insert into score values('105','3-245','75')

insert into score values('109','3-245','68')

insert into score values('103','3-105','92')

insert into score values('105','3-105','88')

insert into score values('109','3-105','76')

insert into score values('101','3-105','64')

insert into score values('107','3-105','91')

insert into score values('108','3-105','78')

insert into score values('101','6-166','85')

insert into score values('107','6-166','79')

insert into score values('108','6-166','81')

select * from student

select * from teacher

select * from course

select * from score

 

--1、 查询Student表中的所有记录的Sname、Ssex和Class列。

select sname from student

select ssex from student

select class from student

--2、 查询教师所有的单位即不重复的Depart列。

select distinct depart from teacher

--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 >=60.0 and degree <=80.0

--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 sno 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。

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 AVG(degree) from score where cno like '3%' group by cno having COUNT(*) >=5

--13、查询最低分大于70，最高分小于90的Sno列。

select sno from score where degree in (select degree from score group by degree having MIN(degree) >70 and MAX(degree)<90)

--14、查询所有学生的Sname、Cno和Degree列。

select Sname,Cno,degree from student inner join score on student.sno = score.sno

--15、查询所有学生的Sno、Cname和Degree列。

select sno,cname,degree from score inner join course on score.cno = course.cno

--16、查询所有学生的Sname、Cname和Degree列。

select Sname,Cname,degree from student inner join score on student.sno = score.sno

inner join course on score.cno = course.cno

--17、查询“95033”班所选课程的平均分。

select AVG(degree) from score inner join student on student.class = '95033'

--18、假设使用如下命令建立了一个grade表：

create table grade(low int,upp int,rank varchar(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,degree,

 

(select rank from grade where degree > low and degree < upp) as rank

 

from score

 

 from score

select * from grade 

 

--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。//无关子查询

select * from score where degree >(select degree from score where sno='109' and cno= '3-105')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 s1 where  degree <(select MAX(degree) from score s2 where s1.sno = s2.sno group by s2.sno having COUNT(*) >1)

    --主查询每查询一行，然后拿着查询出的这一行sno做为参数，放入到子查询中做为条件，在子查询中

    --根椐这个条件筛选出指定的sno，然后对其分组，取得该sno的最大成绩，得到最大成绩后

    --与主查询的成绩对比，如果主查询成绩小，满 足要要求输出主查询的结果

 

--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 YEAR(sbirthday) = (select YEAR(sbirthday) from student where sno = '105') and sno!='105'

--108号同学的出生年月是唯一的;

--23、查询“张旭“教师任课的学生成绩。

select sno,cno,degree from score where cno = (select cno from course inner join teacher on course.tno = teacher.tno and teacher.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 =(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

--27、查询出“计算机系“教师所教课程的成绩表。

select cno,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  tname ,prof from teacher where prof not in 

(select prof from teacher where depart='电子工程系') and depart='计算机系'

union --这个东西将两个查询的结果合并成一个，两个查询的结果必须数量一致，数据类型一致

select  tname ,prof from teacher where prof not in 

(select prof from teacher where depart='计算机系') and depart='电子工程系'

 

select tname ,prof from teacher t1

   where not exists (select * from teacher t2 where t1.prof=t2.prof and t1.tname <>t2.tname)

   --主查询中每取出一行记录，拿着这个记录的prof到子查询中是看看存不存在和自已相同的prof，并且

   --(和自已不同名，如果不存在就打印出主查询取出这行记录)

 

--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 degree >(select MAX(degree) from score where cno = '3-245') and cno = '3-105' 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 cno,sno,degree from score where degree >(select MAX(degree) from score where cno = '3-245') and cno = '3-105'

--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 s1 where s1.degree <(select AVG(degree) from score s2 where s1.cno = s2.cno group by s2.cno)    

          --a.得到每个同学的每门课成绩，和该门课的平均分进行对比

          --b.得到平均成绩

          --c.进行对比

       select sno,s1.cno,degree from score s1 where degree <

         (select avg(degree) from score s2 where s2.cno=s1.cno group by s2.cno )

              --因为主查询和子查询中都会产生cno这一列，要进行区分

              --所以我们给主查询中的表给了一个别名叫s1 ,那么主查询产生的cno就叫s1.cno

                 --子查询中的表给了一个别名叫s2,子查询中cno就叫s2.cno

 

 

--34、查询所有任课教师的Tname和Depart.

select tname,depart from teacher inner join course on teacher.tno = course.tno

--35 查询所有未讲课的教师的Tname和Depart. 

select tname,depart from teacher t where not exists (select * from course c where c.tno =t.tno)

--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,datediff(YEAR,sbirthday,GETDATE()) from student

--39、查询Student表中最大和最小的Sbirthday日期值。

select MAX(YEAR(sbirthday)) as '最大日期',MIN(YEAR(sbirthday)) as '最小日期' 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,datediff(year,sbirthday,getdate())desc

--41、查询“男”教师及其所上的课程。

select tname,cname from teacher inner join course on teacher.tno = course.tno where tsex = '男'

--42、查询最高分同学的Sno、Cno和Degree列。

select * 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') 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 ssex = (select ssex from student where sname = '李军') and

class = (select class from student where sname = '李军') and 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 sname,ssex,cname,degree from course inner join score on course.cno = score.cno

inner join student on score.sno = student.sno where cname = '计算机导论' and ssex = '男'

--46、查询score表中分数最高的学生的信息。//多层嵌套

select student.*,degree from student inner join score on degree = (select MAX(degree) from score) and student.sno = score.sno

--47、查询score表中的平均分在80分以上的学生信息。//相关查询。无关查询

--相关子查询:

select * from student st where exists (select * from score sc where st.sno = sc.sno group by sc.sno having AVG(sc.degree) >80)

--无关子查询:

select *from student where sno in(select sno from score group by sno having AVG(degree) >80)