Mysql自动递增类似数据的int

So this is more of a query of how one might go about doing this, I'm new to MySQL/PHP coding when it comes to more than the basics so I'm just wondering how one might set up an auto incrementing int where if two lastnames were the same it would count them. I was unable to find anything on it while searching online but an example would be:So this is more of a query of how one might go