3 Replies Latest reply on Jan 10, 2017 12:38 PM by Shinichiro Murakami

    Trending Using Several Snapshots of a Dataset

    Neil Brosnahan

      I was wondering if anyone has run into a scenario where you want to trend data that is captured in a series of snapshots (e.g. one snapshot each day).

       

      In my situation I'm looking Servers and I want to know how many Servers have been Added and how many Servers have been removed between daily snapshots.

       

      I was thinking an LOD (Level Of Detail) calculation would work for this so I did:

       

      Added Servers:

      SUM(IF {FIXED [Server Name] : min(Date)}==Date then 1 else 0 end)

       

      Removed Servers:

      -SUM(IF {FIXED [Server Name] : max(Date)}==Date then 1 else 0 end)

       

      The idea being to find out when the Server Name first appeared in the Daily Snapshots and when the Server Name last appeared in the Daily snapshots.

       

      After doing some work to 0 the first date snapshot and the last date snapshot to 0 I came up with the attached Tableau 10.0 Workbook.

       

      While the Added Servers and Deleted Servers look correct the Net difference between snapshots is not correct using the calculation: [Added Servers]+[Removed Servers]

       

      Maybe I went about this the wrong way? Any help would be greatly appreciated! Thank you in advance!

       

      Sincerely,

      Neil