I need someone to point me in the right direction on this. I am trying to track changes in the play counts of the top 500 most played songs in my itunes library. I have been saving my top played list to excel each week with columns for; song, length, artist, album, plays, date added to itunes, and date recorded in excel.

I want to create a formula that will output the difference in play counts between weeks. As the list order changes each week, some songs come on to the list while others fall off, I am unsure how to get excel to find the same song in the two data sets and then tell it to show the difference in the play count column.