近期在学习sql server，老师布置了一些小练习。说实话这些练习题在网上都能找到答案的，可是直接抄答案有什么意思呢？简直是浪费生命！
以下附原题及个人写的sql语句，如有和网上某某的语句相同，只能说纯属雷同了。因为本人不喜欢直接copy某某的东西，学习一定要有一个认真的态度。
原题及答案如下：
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)