3 Replies Latest reply on Sep 20, 2016 11:08 AM by Joe Oppelt

    How to get Running Sum to Exclude the First Data Point?

    Bob Liu



      One of my calculations involve running sums of incremental data points. 2 out of 3 values are incremental data while the third value is calculated using cumulative data.

      The formula looks like this

      RUNNING_SUM([Incremental A]) / (RUNNING_SUM(([Incremental B ]) + RUNNING_SUM(([Incremental C])))


      Incremental B is calculated as Sum([B]) - Lookup(Sum(B), -1) This resulted in a blank value for the first Evaluation Period.

      Usually this is fine as I would just hide the first time period. However, the running sum starts at the first Evaluation Period and I would get an value for A and C , B would be null. At the second period, I would get the sum of Period 1 and 2 for A and C while only getting the B value for period 2. Is there anyone to force tableau to ignore the first Evaluation Period and start the running sum from the second?