MySQL | 修改数据表结构

数据定义语言：字段约束

添加字段

ALTER TABLE student
ADD address VARCHAR(200) NOT NULL,
ADD home_tel char(11) NOT NULL;

修改字段类型和约束

ALTER TABLE student
MODIFY home_tel VARCHAR(20) NOT NULL;

DESC student;

修改字段名称

DESC student;

ALTER TABLE student
CHANGE address home_address VARCHAR(200) NOT NULL;

删除字段

DESC student;

ALTER TABLE student
DROP home_address,
DROP home_tel;

总结语句

ALTER TABLE student # DDL 语句 没有操作数据类型
ADD address VARCHAR(200) NOT NULL,
ADD home_tel char(11) NOT NULL;

ALTER TABLE student # DDL 语句 没有操作数据类型
MODIFY home_tel VARCHAR(20) NOT NULL;

DESC student;

ALTER TABLE student # DDL 语句 没有操作数据类型
CHANGE address home_address VARCHAR(200) NOT NULL;

ALTER TABLE student # DDL 语句 没有操作数据类型
DROP home_address,
DROP home_tel;