CREATE DATABASE test;
use test;
CREATE TABLE student(
s_id int,
s_name varchar(255),
s_sex varchar(255),
s_dapt varchar(255)
);
INSERT INTO student values(1001,'龙政锛','男','计算机');
alter table student add email varchar(200);
alter table student add country varchar(200);
select * from student;
alter table student drop column email;
select * from student;