摘要： //主键 alter table tabelname add new_field_id int(5) unsigned default 0 not null auto_increment ,add primary key (new_field_id);//增加一个新列 alter table t2 add d timestamp;alter table infos add ex tinyint not null default '0';//删除列 alter table t2 drop column c;//重命名列 alter table t1 change a b inte 阅读全文