/**創建班級表*/
create table cla(class_id int(9) NOT NULL AUTO_INCREMENT,classes varchar(255) not null,PRIMARY key (class_id)
)ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1;/**創建學生表*/
ccreate table stu(id int(9) not null AUTO_INCREMENT,name varchar(255) not null,gender enum("男","女"),birth date not null,class_id int(9) not null, PRIMARY key(id),foreign key(class_id) REFERENCES cla(class_id)
)ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1;/**向班級表中插入數據*/
insert into cla(classes) value("一班");
insert into cla(classes) value("二班");
insert into cla(classes) value("三班");/**向學生表中插入數據*/
insert into stu(name,gender,birth,class_id) value("李磊","男","20000127",1);
insert into stu(name,gender,birth,class_id) value("韓梅梅","女","19990301",1);
insert into stu(name,gender,birth,class_id) value("韓冬","男","20000506",1);insert into stu(name,gender,birth,class_id) value("馬冬梅","女","19980821",2);
insert into stu(name,gender,birth,class_id) value("小青","女","19980801",2);
insert into stu(name,gender,birth,class_id) value("小白","男","19990401",2);
insert into stu(name,gender,birth,class_id) value("齊德隆","男","19990620",2);
insert into stu(name,gender,birth,class_id) value("齊東強","男","19990620",2);insert into stu(name,gender,birth,class_id) value("小蘭","女","20000127",3);
insert into stu(name,gender,birth,class_id) value("紅紅","女","19990301",3);
insert into stu(name,gender,birth,class_id) value("薩","女","20000506",3);
insert into stu(name,gender,birth,class_id) value("熊大","男","20000506",3);
/**按班級查找班級總人數*/
select c.classes,count(*) from stu s,cla c where s.class_id = c.class_id group by s.class_id;
/**從學生表和班級表按學生出生時間降序查找學生所有信息*/
select * from stu s,cla c where s.class_id = c.class_id order by birth DESC;
/**刪除id為12的學生信息*/
delete from stu where id = 12;/**更新id為11的學生姓名為颯颯*/
update stu set name="颯颯" where id = 11;
