6 Replies Latest reply on Sep 15, 2014 12:15 PM by Ron Chipman

    Does blending data from two data sets only give me an inner join of that data?

    David Woollard

      Currently I am using Tableau 8.1.6.  I have two data sets which I am trying to blend.  One is an Oracle database data source and the other is an Excel spreadsheet.  A common control number connects the two data sources.  SOME of the records in the Oracle database are connected to ALL the records in the Excel spreadsheet via the control number and SOME Oracle database records are NOT because they do not have any control numbers in common. When I data blend using the control number, what seems to happen is that I get an inner join of the two data sources (that is, I only see only records that share a common control number).  This seems to prevent me from being able to view records in the Oracle database that DO NOT have corresponding control numbers in the Excel spreadsheet.  In turn this prevents me from being able to have Tableau automatically calculate the percentage of the Oracle database records to which the Excel spreadsheet is able to connect to using the control number.  Although I could do this calculation by hand once, this calculation is a critical metric that changes daily as the Oracle database and the Excel spreadsheet grow every day.  So here are my questions:

      1) Does data blending  between an Oracle and Excel data source merely do an "inner join"?

      2) If not, what am I doing wrong--I need to achieve a "left join" using data blending?


      I cannot attach the workbook due to data sensitivities.