1 Reply Latest reply on Aug 13, 2018 2:50 PM by Don Wise

    How to creat calculated field across blended data sources

    John Lee

      Hi, I want to be able to take date information from my data source 1 and use it on data source 2.


      Whenever I try to make a calculated field using date from data source 1, it does ATTR(data source 1 . Date). This aggregation prevents me from making further calculations. Is there any way to overcome the problem? Thank you

        • 1. Re: How to creat calculated field across blended data sources
          Don Wise

          Hi John,


          That would be a standard issue w/Data Blending.  Tableau automatically treats Data Blending as a LEFT JOIN.  I find it useful for bringing in disparate data fields that have some common data points for DISPLAY purposes but not for any extensive calculations.  That's where it will bog down.


          Is there a reason you couldn't do a JOIN within the Data Pane Window using the common/unique fields? Select your primary data source first, then go to Data Source then Add new data source (whatever you're secondary data source is that you're currently blending to).  Tableau behaves much better w/JOINED or UNIONED data.


          Also, without a workbook it's hard to tell if the calculated field you're working on will work in some other manner.  If it's proprietary, can you mock some data up in a packaged workbook and post?


          Thx, Don