Can you really perform php file using mysql saved procedure or event scheduler?

So far as I am aware this really is impossible. And That I can't really make a scenario where you'd do. Can't you plan a task with cronjob/task scheduler that executes a PHP file without anyone's knowledge?

No, that's difficult. What exactly are your intentions for doing things for?

This type of feature is not implemented within the MYSQL server (yet?), but you may be thinking about