create database mydb3gouse mydb3 create table student(    --学号    sno varchar(3) not null primary key,    --姓名    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))create table teacher(    --教工编号    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))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) references teacher(tno))create table score(    --学号    sno varchar(3) not null references student(sno),    --课程号    cno varchar(5) not null references course(cno),    --成绩    degree decimal(4,1))insert into studentvalues(‘108‘,‘曾华‘,‘男‘,‘1977-09-01‘,‘95033‘)insert into studentvalues(‘105‘,‘匡明‘,‘男‘,‘1975-10-02‘,‘95031‘)insert into studentvalues(‘107‘,‘王丽‘,‘女‘,‘1976-01-23‘,‘95033‘)insert into studentvalues(‘101‘,‘李军‘,‘男‘,‘1976-02-20‘,‘95033‘)insert into studentvalues(‘109‘,‘王芳‘,‘女‘,‘1975-02-10‘,‘95031‘)insert into studentvalues(‘103‘,‘陆君‘,‘男‘,‘1974-06-03‘,‘95031‘)insert into teachervalues(‘804‘,‘李诚‘,‘男‘,‘1958-12-02‘,‘副教授‘,‘计算机系‘)insert into teachervalues(‘856‘,‘张旭‘,‘男‘,‘1969-03-12‘,‘讲师‘,‘电子工程系‘)insert into teachervalues(‘825‘,‘王萍‘,‘女‘,‘1972-05-05‘,‘助教‘,‘计算机系‘)insert into teachervalues(‘831‘,‘刘冰‘,‘女‘,‘1958-08-14‘,‘助教‘,‘电子工程系‘)insert into coursevalues(‘3-105‘,‘计算机导论‘,‘825‘)insert into coursevalues(‘3-245‘,‘操作系统‘,‘804‘)insert into coursevalues(‘6-166‘,‘数字电路‘,‘856‘)insert into coursevalues(‘9-888‘,‘高等数学‘,‘831‘)insert into scorevalues(‘103‘,‘3-245‘,‘86‘)insert into scorevalues(‘105‘,‘3-245‘,‘75‘)insert into scorevalues(‘109‘,‘3-245‘,‘68‘)insert into scorevalues(‘103‘,‘3-105‘,‘92‘)insert into scorevalues(‘105‘,‘3-105‘,‘88‘)insert into scorevalues(‘109‘,‘3-105‘,‘76‘)insert into scorevalues(‘101‘,‘3-105‘,‘64‘)insert into scorevalues(‘107‘,‘3-105‘,‘91‘)insert into scorevalues(‘108‘,‘3-105‘,‘78‘)insert into scorevalues(‘101‘,‘6-166‘,‘85‘)insert into scorevalues(‘107‘,‘6-166‘,‘79‘)insert into scorevalues(‘108‘,‘6-166‘,‘81‘)select * from studentselect * from teacherselect * from courseselect * from score--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 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 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,degree desc--9、 查询‘95031‘班的学生人数。select COUNT(*) ‘人数‘ 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=    (    select cno 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    group by sno    having MIN(degree)>70 and MAX(degree)<90--14、查询所有学生的Sname、Cno和Degree列。select student.sname,score.cno,score.DEGREE from score    join student on student.sno=score.sno--15、查询所有学生的Sno、Cname和Degree列。select score.sno,course.cname,score.DEGREE from score    join course on course.cno=score.cno--16、查询所有学生的Sname、Cname和Degree列。select student.sname,course.cname,score.DEGREE from score    join student on student.sno=score.sno    join course on course.cno=score.cno--17、查询‘95033‘班所选课程的平均分。select AVG(degree) from score        where sno in    (        select sno from student        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,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 distinct sno,cno,RANK from score    join grade on score.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 student    where sno in    (    select sno from score        where cno=‘3-105‘ and degree>        (        select degree from score            where cno=‘3-105‘ and sno=‘109‘        )    )--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    where cno not in    (    select cno from score        where degree=        (        select MAX(degree) from score        )    )    and cno in    (    select cno from score        group by cno        having COUNT(cno)>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 cno=‘3-105‘ and degree>    (    select degree from score        where cno=‘3-105‘ and sno=‘109‘    )--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=108    )--23、查询‘张旭‘教师任课的学生成绩。select score.* from score    join course on score.cno=course.cno    join teacher on course.tno=teacher.tno    where tname=‘张旭‘select score.* from score,course,teacher    where score.cno=course.cno    and course.tno=teacher.tno    and 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 distinct tname from teacher    join course on course.tno=teacher.tno    join score on score.cno=course.cno    where score.cno=        (        select cno from score            group by cno            having COUNT(cno)>5        )--25、查询95033班和95031班全体学生的记录。select * from student    where class in (95033,95031)--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 distinct score.* from score    join course on course.cno=score.cno    join teacher on teacher.tno=course.tno    where teacher.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 t1 where depart=‘计算机系‘ and  not exists(select * from teacher t2 where depart = ‘电子工程系‘ and t1.prof = t2.prof)unionselect * from teacher t1 where depart=‘电子工程系‘ and  not exists(select * from teacher t2 where depart = ‘计算机系‘ and t1.prof = t2.prof)--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 >(select MAX (degree) from score where cno = ‘3-245‘)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Degreeselect * from score s1 where sno in(select sno from score where cno in (‘3-105‘,‘3-245‘) group by sno having COUNT(*) > 1) and cno = ‘3-105‘ and degree >(select degree from score s2 where sno in(select sno from score where cno in (‘3-105‘,‘3-245‘) group by sno having COUNT(*) > 1) and cno = ‘3-245‘ and s1.sno = s2.sno)--31、查询所有教师和同学的name、sex和birthday.select sname,ssex,sbirthday from studentunionselect 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‘unionselect 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。--求每门课的平均分--求低于平均分的成绩select * from score  s1 where degree <(select cno,AVG(degree) from score s2 where s1.cno = s2.cno  group by cno )--34、查询所有任课教师的Tname和Depart.select distinct tname,depart from teacher    --35  查询所有未讲课的教师的Tname和Depart. select tname ,depart  from teacher   left join course on teacher .tno  =course .tno   left join score on course .cno = score.cno   where score .sno is null      select tname,depart from teacher where tno in  (  select * from course where cno not in  (  select distinct cno from score   )  )--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(*)>1    --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) 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,sbirthday asc--41、查询‘男‘教师及其所上的课程。select course.* from teacher    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‘    )--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‘    )--45、查询所有选修‘计算机导论‘课程的‘男‘同学的成绩表。select student.* from score    join course on course.cno=score.cno    join student on student.sno=score.sno    where course.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。select * from student    where sno=    (    select sno from score        where degree=        (        select MAX(degree) from score        )    )--47、查询score表中的平均分在80分以上的学生信息。select * from score select * from student select * from student where sno in(select sno from score group by sno having AVG (degree )>80)