title: Difference between two filtered row Spotfire
body: <p>I'm in problems with Spotfire.  I have filtered my dataset by feature (dat_delivery) and I would like to make de difference between rows with the same dateprice. I know that spotfire have the difference aggregation method but it doesn't work. (I'm a Rookie)
  Any idea?</p>
  <p>Thanks
  <a href="https://i.stack.imgur.com/SXNJ3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SXNJ3.png" alt="enter image description here" /></a></p>