使用 Data Grip 创建 MySQL 表使用 auto_increment 时，为什么该软件仍将主键单独拿出来声明?

[Kamitora]

Example

create table friend_request
(
	friend_request_ID int auto_increment,
	request_num int default 0 not null,
	user_name_sent varchar(20) not null,
	id_sent int not null,
	id_received int not null,
	is_received bool default 0 not null
);

alter table friend_request
	add constraint friend_request_pk
		primary key (friend_request_ID);

出现如下错误

[42000][1075] Incorrect table definition; there can be only one auto column and it must be defined as a key.

要手动把语句改成这样

	friend_request_ID int auto_increment PRIMARY KEY,