[mysql] How to get the next auto-increment id in mysql

You can't use the ID while inserting, neither do you need it. MySQL does not even know the ID when you are inserting that record. You could just save "sahf4d2fdd45" in the payment_code table and use id and payment_code later on.

If you really need your payment_code to have the ID in it then UPDATE the row after the insert to add the ID.