Update field on the same table


I have 4 fields, "Name", "Email", "Supervisor's name" and "Supervisor's Email"

How do I do a query to fill up the Supervisor's Email column based on the field Supervisor's name and then find his/her email on the same table ?

If you can create the supervisor's email address based on his/her name, there is not need to fill a field with it. Just create it and you have it.