show databases; #显示数据库 use 数据库名;#使用数据库 create table tbstudent (stuid int
primary key auto_increment, stuname varchar(10) not null,cassid int not
null);#创建tbstudent表,主键stuid insert into tbstudent values(1,'zhangsan',1);#插入数据
create table tbcourse (csid int primary key auto_increment, csname varchar(10)
not null); insert into tbcourse values(1,'python');#插入数据 create table tbsc(scid
int primary key auto_increment,sid int not null,cid int not null,foreign
key(sid) references tbstudent(stuid),foreign key(cid) references
tbcourse(csid));#主键scid,学生主键sid,班级主键cid insert into tbsc values
(default,2,1);#插入数据 select t1.stuid,t1.stuname,t2.csname from tbstudent t1 join
tbsc t3 on t3.sid=t1.stuid join tbcourse t2 ON t2.csid=t3.cid order by
t1.stuid;#查询所有学生选课信息(学生编号,学生名称,课程名称)