How to set auto-increment field in existing table in mysql

Mysql method to set auto-increment fields in an existing table: 1. Add a field, the code is [alter table xiami add id int;]; 2. Modify the field, the code is [alter tabel xiami change id id auto_increment].

The operating environment of this tutorial: Windows 7 system, mysql version 8.0.22, DELL G3 computer. This method is suitable for all brands of computers.

Related free learning recommendations: mysql video tutorial

mysql sets auto-increment in existing tables Field method:

Step 1: Add field

alter table xiami add id int;

Step 2: Modify field

alter tabel xiami change id id auto_increment not null primary key;

Question:

Records in the table The number is 3929966

Query OK, 3929966 rows affected (2 min 8.09 sec)
Records: 3929966  Duplicates: 0  Warnings: 0　　
查看创建表命令时,auto_increment为3932618
>> show create table xiami;
...
ENGINE=InnoDB AUTO_INCREMENT=3932618 DEFAULT CHARSET=utf8

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