alter table products add primary key id auto_increment mysql code example
Example 1: add auto_increment column to existing table mysql
ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY
ALTER TABLE `users` ADD `id` INT NOT NULL AUTO_INCREMENT UNIQUE FIRST
Example 2: how to change the auto increment in existing table mysql
ALTER TABLE tbl_access ADD COLUMN `access_id` int(10) NOT NULL PRIMARY KEY AUTO_INCREMENT FIRST