7 Replies Latest reply on May 8, 2019 10:12 AM by Jonathan Drummey

    Tableau Prep Input Node Collation Mismatch Error

    Baker Lee

      I cannot get my Prep flow to run as it is giving me the system error below.

       

      My flow has 3 inputs: two CSVs (~10MB and ~150 MB) and one .hyper output from another flow (~200 kb). The flow usually takes a minute to load, and after the first time, the flow usually executes correctly. This error only started today after I saved over the input files with new data of the same name and file path.

       

      Here is the exact text of the error:

      System Error: Unable to run input node: Failure evaluating to database: ERROR: collation mismatch, use COLLATE statements to resolve

       

      Please help me as there is nothing I have found to solve this issue and it is crucial to my daily workflow. Let me know if I can provide any more information.

       

      Thanks to anyone who can help!

       

        • 1. Re: Tableau Prep Input Node Collation Mismatch Error
          Jonathan Drummey

          Hi, I'd suggest reaching out to Tableau support on this one.

          • 3. Re: Tableau Prep Input Node Collation Mismatch Error
            Bruce Segal

            Hi Baker Lee I got a similar message using the version of Superstore data that comes with Tableau Prep; 'System error: Unable to run input node. Failure evaluating to database, all inputs to union must have matching column types."

             

            See screen shot below.

             

            This happened to me twice now in the same situation and I'm frustrated. I've had to rebuild my flow from scratch twice now, which gives me no confidence in Tableau Prep for when I use it with real data.

             

            It happened in the same situation. I had the flow up and working well. And then I made a change to one of the data inputs that feed into a Union. In this case I "un-removed" one column that I had "removed" in the input step, and removed a different one. They're effectively the same columns, and both were measures, in decimal data format. The only visible difference is that they had different column names.

             

            The result is that no data displays when I click on the Union 1. That result is consistent with the error message, but there's no information in the error message to help me diagnose if I did something wrong, or which fields are not "matching column types."

             

             

             

            • 4. Re: Tableau Prep Input Node Collation Mismatch Error
              Nick Fryars

              I have the same problem. I am trying to create a financial consolidation flow by performing a simple left join of a table with a filtered wildcard union of tables. Nothing I have tried works.

              2019-05-08.png

              • 5. Re: Tableau Prep Input Node Collation Mismatch Error
                Jonathan Drummey

                Hi Nick,

                 

                I strongly suspect what you’re seeing and the earlier post are actually different issues. The union issue from earlier in the thread was reported in the union step as a column mismatch error. In your case from the screenshot what I’m seeing is a collation error (a different error type) in the join step (a different step).

                 

                In general collation is about how data is sorted and how differently cased & accented characters are treated. For example whether MINNESOTA and Minnesota treated as the same thing (or not) for purposes of sorting, joins, etc. I’m guessing that the different inputs are from different sources and Tableau Prep’s underlying Hyper engine is having a hard time resolving the differences. In some databases it’s possible to change the collation on the fly (so you could do it in Custom SQL in the Input step), so that could be one way of working around this. I’d also suggest reaching out to Tableau support on this as well.

                 

                Jonathan

                • 6. Re: Tableau Prep Input Node Collation Mismatch Error
                  Nick Fryars

                  Jonathan Drummey, thanks for highlighting the point about collation and the fact that the steps were different. However, what's happening here is that I'm trying to join two sets of 4-digit General Ledger account numbers formatted as text and stored in similar tables in a single database (single datasource), so no accents or strange characters. The join works perfectly in Tableau Desktop but not in Prep. It seems like a bug to me and I have raised a support case. Nick

                  • 7. Re: Tableau Prep Input Node Collation Mismatch Error
                    Jonathan Drummey

                    Thanks for the clarification...personally I agree with you, if I can do X task in Tableau Desktop and Tableau Prep claims to do the same thing and can't then I'd call that a bug as well!

                     

                    Jonathan