检查目录中不在mysql数据库中的文件

I have this code which checks if there are any filenames in my database table "files" which are not in the directory "video/test". I have been trying to edit this code so that it does the opposite i.e it checks if there are any filenames in the directory "video/test" which are not in the database table "files". I am having some trouble switching the content to the other side of the clause. I'm getting mysql syntax errors. Can anyone help me out with thisI have this code which checks if there are any