Views filter: how to compare two fields?
Not sure you are going to use it, but for those who may get here looking for the same:

Under the Filter Criteria, Search for "Globals: Fields Comparison".
For the record, the fields you want to compare should be among the fields you are loading in the current View.

So, if you want to compare to something you are not willing to show, you should add the fields to the View and check the Exclude from display.

Hope it helps!