email filter in yahoo mail is that enuff>?

Not enough info provided. I guess I should have said current/saved emails already in folders. As an example, there is a folder called Y already in Ymail. Let's say there are pages and pages of emails from PersonX, PersonY and PersonZ. I want to be able to do a "DCOUNT" (database count") function, such as "Count all the emails in folder Y Where Subject Contains "Person Z". This would return a number such as 387 (emails) . I don't want to delete ANY of the other emails and I don't want to have to go thru page by page and manually count them. I am probably SOL.