5 Replies Latest reply on Oct 29, 2018 3:35 PM by Kyle Yetter

    Need Creative Way to Fix Data Source Error

    Katie Meyer

      Hello Tableau Community!


      First post, so please bear with me.  I am using 2 different data sources and blending them - the primary data source includes invoiced sales and the secondary data source includes credits/returns applied to the invoices.


      My issue is that I have an error in my data source that I am hoping to fix in Tableau.  I have been told by my IT team that it is not possible to retroactively make a correction in the database itself so I need to come up with a solution in Tableau. 


      The actual scenario is as follows: A customer is being credited for a product they did not actually purchase.  A credit was accidentally, erroneously applied to a product very similar to the item the customer actually purchased.  Because there is no record of the customer actually purchasing this item in the primary data source, the credit (from secondary data source) is not showing up in Tableau.  In reality, the customer was actually refunded the money.  Without the credit showing in Tableau, any calculations or sales totals are overstated by the amount of this "missing" credit.


      How can I solve this without going back to the actual data source?  Is it even possible?


      See attached twbx from Tableau 2018.  Note - within the file I have displayed captions with more specific information.

        • 1. Re: Need Creative Way to Fix Data Source Error
          Yuriy Fal

          Hi Katie,


          You can use Tableau to quickly find mistakes --

          as you've done already using your second view.


          But to repair mistakes, the new (correcting) transactions

          should be added to (written into) the original datasource(s).


          Tableau can't do that (it is not even indented to do),

          but your 'transactional application' can --

          with the help of a human, of course ;-)




          • 2. Re: Need Creative Way to Fix Data Source Error
            Katie Meyer



            Thank you for your response. 


            Due to business processes, I am unable to write back changes to the datasource so it appears that in this particular instance I may be stuck. 


            You have confirmed by fear, but it does mean my thoughts were right about Tableau and at least I can say I am learning something!  Thanks again.




            • 3. Re: Need Creative Way to Fix Data Source Error
              Kyle Yetter

              Hi Katie,


              Rather than blending, could you join the Invoice and Credit tables with an outer join?  That way you would tie the invoices and corresponding credits together, but would also get all invoices without a credit, as well as all credits without an invoice. On the surface, it appears that your tables are in the same database.




              • 4. Re: Need Creative Way to Fix Data Source Error
                Katie Meyer



                Thanks for your response. 


                I too thought a join would work but the data sources are collated differently and I get a collation error message when trying to join.  I don't know SQL so I don't have a way around that issue either.  Hence the blending.

                • 5. Re: Need Creative Way to Fix Data Source Error
                  Kyle Yetter

                  That's strange, most of the issues I can find with collation errors happen with Excel or csv files rather than databases. But yeah, with the way blending works, I don't think you'll be able to get the result you want with a blend. Could you possibly reach out to your IT team to assist in a quick outer join query that you could pull in with Custom SQL?


                  Sorry can't be of more help!