创建一个缺少userId的数组，之前已从mysql数据库中删除

Okay. I've got a mysql database full of users and they're corresponding information. They are assigned an auto incremented userId and directory in a users folder when account is created. Through out the past few months many of these rows have been deleted (accounts removed) from the database. My problem is when the row is removed from the database the directory for that user remains. I now have possibly thousands of folders for users that will never be used. Ive got an array of useless directories. Problem I have is there is a difference of 16 that will be deleted. Where is this difference coming from?? Okay. I've got a mysql database full of users a