创建表格时添加：create table table1(id int auto_increment primary key,...)创建表格后添加：删除原有主键：ALTER TABLE `table_name` DROP `id`;alter table table1 add id int auto_increment primary key 自增字段，一定要设置为primary key.例子alter table tablename drop column id;alter table tablename add id mediumint(8) not null primary key auto_increment first;方法二：alter table tablename auto_increment=0