1.学生表（student）

create table student(sno varchar(3),sname varchar(10) not null,ssex varchar(3),sbirthday datetime,class varchar(5) not null,primary key(sno))engine=innodb default charset=utf8;

2.课程表
create table course(cno varchar(10),cname varchar(30) not null,tno varchar(10),primary key(cno))engine=innodb default charset=utf8;

3.成绩表
create table grade(sno varchar(3),cno varchar(5),degree tinyint not null,primary key(sno,cno));

4.教师表
create table teacher(tno varchar(5),tname varchar(20) not null,tsex varchar(2),tbirthday datetime,prof varchar(20) not null,depart varchar(30) not null,primary key(tno))engine=innodb default charset=utf8;

5.等级表
create table rank(down tinyint not null,up tinyint not null,rank varchar(2),primary key(rank))engine=innodb default charset=utf8;

6.将下列数据插入表中
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (108 ,'曾华' ,'男' , '1977-09-01',95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (105 ,'匡明' ,'男' ,’1975-10-02’,95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (107 ,'王丽' ,'女' ,’1976-01-23’, 95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (101 ,'李军' ,'男' ,’1976-02-20’,95033);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (109 ,'王芳' ,'女' ,’1975-02-10’,95031);
INSERT INTO STUDENT (SNO,SNAME,SSEX,SBIRTHDAY,CLASS) VALUES (103 ,'陆君' ,'男' ,’1974-06-03’,95031);

INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-105' ,'计算机导论', '825');
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('3-245' ,'操作系统' , '804');
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('6-166' ,'数据电路' , '856');
INSERT INTO COURSE(CNO,CNAME,TNO)VALUES ('9-888' ,'高等数学' , '100');

INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES ('103','3-245',86);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (105,'3-245',75);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (109,'3-245',68);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (103,'3-105',92);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (105,'3-105',88);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (109,'3-105',76);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (101,'3-105',64);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (107,'3-105',91);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (108,'3-105',78);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (101,'6-166',85);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (107,'6-106',79);
INSERT INTO GRADE(SNO,CNO,DEGREE)VALUES (108,'6-166',81);

INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (804,'李诚','男','1958-12-02','副教授','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (856,'张旭','男','1969-03-12','讲师','电子工程系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (825,'王萍','女','1972-05-05','助教','计算机系');
INSERT INTO TEACHER(TNO,TNAME,TSEX,TBIRTHDAY,PROF,DEPART)
VALUES (831,'刘冰','女','1977-08-14','助教','电子工程系');

insert into rank(down,up,rank) values(90,100,'A');
insert into rank(down,up,rank) values(80,89,'B');
insert into rank(down,up,rank) values(70,79,'C');
insert into rank(down,up,rank) values(60,69,'D');
insert into rank(down,up,rank) values(0,59,'E');

sql语句练习：
1、 查询Student表中的所有记录的Sname、Ssex和Class列。

2、 查询教师所有的单位即不重复的Depart列。

5、 查询Grade表中成绩为85，86或88的记录。

11、查询‘3-105’号课程的平均分。

12、查询Grade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。
mysql> select avg(degree) as '平均成绩' from grade 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。

)>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。
mysql> select * from grade where degree>(select degree from grade 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。
mysql> select sno as Sno,sname as Sname,sbirthday as Sbirthday from student where sbirthday=(select sbirthday from student where sno='108');

23、查询“张旭“教师任课的学生成绩。
mysql> select s.sname,g.degree from student as s join grade as g on s.sno=g.sno join course as c on g.cno=c.cno join teacher as t on c.tno=t.tno where t.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。
mysql>select tname from teacher as t join course as c on t.tno=c.tno where c.cno=(select cno from grade group by cno having count(

27、查询出“计算机系“教师所教课程的成绩表。
mysql> select sname as '学生',cname as '课程名',tname as '老师',depart as '院系',degree as '成绩' from student as s join grade as g on s.sno=g.sno join course as c on g.cno=c.cno join teacher as t on c.tno=t.tno where t.deprt='计算机系' order by cname;

28、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”的同学最低分的Cno、Sno和Degree,并按Degree从高到低次序排序。
mysql> select cno as Cno,sno as Sno,degree as Degree from grade where cno='3-105' and degree>(select min(degree) from grade where cno='3-245') order by Degree desc;

29、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.
mysql> select sno from grade where sno in ( select sno from grade where cno='3-105' and sno in ( select sno from grade where cno='3-245')) and cno='3-105' and degree in(select max(degree) from grade where sno in (select sno from grade where cno='3-105' and sno in ( select sno from grade where cno='3-245')) group by sno);

30、查询所有教师和同学的name、sex和birthday.
mysql> select sname as name,ssex as sex,sbirthday as birthday from student union select tname,tsex,tbirthday from teacher;

31、查询所有“女”教师和“女”同学的name、sex和birthday.
mysql> select sname as name,ssex as sex,sbirthday as birthday from student where ssex='女' union select tname,tsex,tbirthday from teacher where tsex='女';