ALTER TABLE student
ADD address VARCHAR(200) NOT NULL,
ADD home_tel char(11) NOT NULL;
ALTER TABLE student
MODIFY home_tel VARCHAR(20) NOT NULL;
DESC student;
DESC student;
ALTER TABLE student
CHANGE address home_address VARCHAR(200) NOT NULL;
DESC student;
ALTER TABLE student
DROP home_address,
DROP home_tel;
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;