4 Replies Latest reply on Jan 30, 2013 1:46 PM by Karen Satke

    Creating relational data from multiple data sources

    aubreyprice

      I'm struggling with calculated fields using fields from 2 separate datasources.  The reason for this is that I am forced to aggregate the values used in the calculation

       

      After investigation I've come across this in the Tableau documentation:

       

      "Note:

      You can aggregate measures using Tableau only for relational data sources."

      I would have thought that if you'd defined a relationship in Tableau between 2 datasources they become "relational"?

        • 1. Re: Creating relational data from multiple data sources
          Tracy Rodgers

          Hi Aubrey,

           

          The "relational data source" refers to the data source itself. In Tableau, a relational data source can be an Excel workbook, an Access database, a comma delimited text file, a MySQL database, an Oracle database, a SQL Server database, a Firebird database, a PostgreSQL database, or a Tableau Data Extract file. This is compared to a multi-dimensional data source, such as a Microsoft Analysis Services cube or an Oracle Essbase cube.

           

          When blending data, the secondary data source is already aggregated, and thus whatever field from the primary source will need to be aggregated as well in the calculation. Would it be possible to post a screenshot of the calculation that you are trying to create?

           

          -Tracy

          • 2. Re: Creating relational data from multiple data sources
            aubreyprice

            Tracy,

             

            Thanks for your response.  If I understand your point, I think you've essentially answered the question when you say  "when blending a data source the secondary source is already aggregated".  Ideally what I'd need to do is create a relationship "pre" aggregation which is not possible with Tableau ??? It would be good if you could blend datasource in the same way that you can join tables in a SQL query

            • 3. Re: Creating relational data from multiple data sources
              Aaron Hayden

              Aubrey,

               

              Have you found a solution for your issue? I'm working through a similar scenario and was disappointed to find that Tableau will only aggregate secondary data when blending.  Let me know if you've uncovered a work around!

               

              Best,

              Aaron

              • 4. Re: Creating relational data from multiple data sources
                Karen Satke

                Hello All,

                I have been trying a work around for the last 3 months and have had no luck.  I read in another post that a Parameter will filter before the aggregation happens, but I have had no luck getting it to work.  I've set parameter filters with the primary source and the secondary source and neither worked.

                 

                Good Luck to Us,

                 

                Karen