[Mysql] 컬럼 추가, 수정, 삭제

컬럼 추가

alter table [table_name] add [column_name] [type] [option]; 
ex. alter table mytable add mycolumn varchar(128) not null default 'mydefault';

컬럼 타입 변경

alter table [table_name] modify [column_name] [type]; 
ex. alter table mytable modify mycolumn varchar(64);

컬럼 삭제

alter table [table_name] drop [column_name];
ex. alter table mytable drop mycolumn;

컬럼명 변경

alter table [table_name] change [before_name] [after_name] [type];
ex. alter table mytable modify beforeMyColumn afterMyColumn varchar(256);