MySQL数据库列的增删改实现方法

CREATE TABLE user_info(
id INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
username CHAR(20) NOT NULL DEFAULT '',
gender TINYINT UNSIGNED NOT NULL DEFAULT 0,
weight TINYINT UNSIGNED NOT NULL DEFAULT 0
)ENGINE=MyISAM DEFAULT CHARSET=utf8;

alter table user_info add height tinyint unsigned not null default 0;

alter table user_info drop height;

alter table user_info add height tinyint not null default 0 after username;

alter table user_info change height shengao smallint not null default 0;

alter table user_info modify shengao tinyint not null default 0;