mysql如何变更自增主键id起始值

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT COMMENT 'ID',
  `name` varchar(50) NOT NULL COMMENT '用户名',
  `age` int(11) NOT NULL COMMENT '年龄',
  `create_datetime` datetime NOT NULL COMMENT '创建时间',
  `update_datetime` datetime NOT NULL COMMENT '更新时间',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8

SELECT auto_increment FROM information_schema.tables where table_schema="account" and table_name="user";

SHOW table STATUS like 'user'

alter table user AUTO_INCREMENT=500

drop table if exists `trace_test`;

CREATE TABLE `trace_test` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ;

alter table `trace_test` AUTO_INCREMENT=10000;

insert into `trace_test`(`name`)values('name2');
select * from `trace_test`;
Result:

id     name
10000  name2

drop table if exists `trace_test`;

CREATE TABLE `trace_test` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT 10000 DEFAULT CHARSET=utf8 ;

insert into `trace_test`(`name`)values('name2');
select * from `trace_test`;
Result：

id     name
10000  name2

drop table if exists `trace_test`;

CREATE TABLE `trace_test` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ;

insert into `trace_test`(`name`)values('name1');
select * from `trace_test`;

truncate table `trace_test`;
alter table `trace_test` AUTO_INCREMENT=10000;

insert into `trace_test`(`name`)values('name2');
select * from `trace_test`;
Result1:

id     name
10000  name
Result2:

id     name
10000  name2

drop table if exists trace_test;

CREATE TABLE trace_test (
  id int(20) NOT NULL AUTO_INCREMENT,
  name varchar(255) DEFAULT NULL,
  PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ;

insert into trace_test(name)values('name1');
select * from trace_test;

delete from `trace_test`;

alter table trace_test AUTO_INCREMENT=10000;

insert into trace_test(name)values('name2');
select * from trace_test;
Result1:

id     name
10000  name
Result2:

id     name
10000  name2