3 Replies Latest reply on Feb 12, 2013 8:44 AM by Joshua Milligan

    Tabulating Nulls

    Olga Polyakov

      Hi All,

       

      I have a data set of student grades which includes some "I" for "Incomplete". 

       

       

      Tableau creates a column of "Null" for these data rows which is fine.  However, when making the table, the Null instances have a count of 0.

       

      Original Data

       

      Capture.JPG

       

       

      Tableau Cross tab

       

      Capture.JPG

       

      Why aren't the "I" being counted properly? 

       

      Thanks,

      Olga

        • 1. Re: Tabulating Nulls
          Joshua Milligan

          Olga,

           

          If you are using an aggregate calculation such as COUNT or COUNTD, then nulls will be eliminated (thus the 0).

           

          If that is the case, try changing your calculation to something like:

           

          COUNT(ZN([Grade]))

           

          The ZN (zero null) will cause the nulls to be evaluated as zeros (for the purpose of the count) and thus they won't be eliminated.

           

           

          If that's not the issue, please post a packaged workbook.  I'd love to take a look and see if there is something else going on.  I realize your data is probably sensitive, so you may need to make it anonymous by replacing names with random IDs, etc...

           

          Joshua

          • 2. Re: Tabulating Nulls
            Olga Polyakov

            Hi Joshua,

             

            Thanks!  That totally worked. 

             

            Since I was making a custom set of bins, I tried setting something into the if then statement that said if "I' then "Incomplete" but that didn't work.  Do you know how I might relabel that Null column as incomplete?

             

            Thanks,
            Olga

            • 3. Re: Tabulating Nulls
              Joshua Milligan

              Olga,

               

              Sure!  If you right click the field on the left under Dimensions, select "Field Properties" then "Aliases", you'll get a window containing all the values with an option to supply an alias -- the value that will actually show on the visualization.  You can change the alias for NULL to "Incomplete"

               

              aliases.PNG

              Joshua

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