2 Replies Latest reply on Sep 4, 2019 9:54 AM by Dimitri Kourouniotis

    Prep Output from Aggregate cell produces 0 rows; however Preview in Desktop is correct

    Dimitri Kourouniotis

      Good Morning!

       

      My output from this aggregation produces 0 rows (Figure 1 and 2).

      The aggregation inspection is showing 283 rows as expected (Figure 3)

      Preview in Tableau Desktop produces the correct result (Figure 4)

      Moving the output to the earlier cell also produces the expected number of rows before the aggregation.

       

      This data originates from a custom SQL statement, XLXS and CSV files.

      Changing the output to .tde or .csv also produced the same 0 rows result. Publish to a data source is also showing as 0 rows.

       

      I created a CSV of the SQL data to possibly upload here for reproduction but the output discrepancy did not appear.

      I would prefer not to have to add an additional Prep flow for our customer to manually run.

       

      The aggregation task is selecting the minimum timestamp when a user has a tie score, to pick the earliest of those scores.

      The data is a concatenation of their score and timestamp.

      I am using Prep Builder 2019.2.3

       

      Thank you for any help.

       

      Figure 1

      Figure 2

      Figure 3

       

      Figure 4

        • 1. Re: Prep Output from Aggregate cell produces 0 rows; however Preview in Desktop is correct
          Matt Bleakley

          The 2019.2.3 build of Prep Builder has a bug in the Aggregation (I spent about a week working with Tableau Tech Support narrowing the problem down to an aggregation I had in my flow and then going through the logs to find the problem).  In my case, the logs showed that some of the Grouped Fields were getting unlinked and then couldn't be found when the flow got to the Aggregation (even though they showed up in the Aggregation window).  Aside from waiting for 2019.3 to be released (hopefully the fix will be in it), you can do a couple of things:  I had to replace my aggregates with custom SQL queries to handle the aggregation on the server side (that might not be an option for you depending on what the data source is you're reading from).  You can also try adding a new aggregation branch to the Clean 12 step and then add a new Output to that.  If that Output looks good, you should just need to delete the old aggregation and break the flow and then add the new one in it's place.  That worked maybe 50% of the time for me but not completely.

          1 of 1 people found this helpful
          • 2. Re: Prep Output from Aggregate cell produces 0 rows; however Preview in Desktop is correct
            Dimitri Kourouniotis

            Hi Matt

             

            Thanks for your considered response!

             

            In terms of using Custom SQL, that won't be possible for this situation since I am specifically using Prep to join a CSV file to my own custom SQL query.

             

            For adding another aggregation branch, I tried that and the result with the bug was the same.