3 Replies Latest reply on Mar 20, 2015 3:09 PM by

    One to Many Join Causing Replication of Data

    Benjamin Hoppe

      I have a multi-table data source. One table contains a master record list of all the primary information. Secondary tables are being left joined to this table which have additional attributes for the records which I am bringing it to be additional dimensions on the dashboard.

       

      When I join the tables, I am getting multiple records for each record from the master record list because of the one-to-many relationship between the additional attributes. There are two key things I need to measure; the record count and the currency value of the records. When seeking the record count, I perform a COUNTD to the unique key of the master record list and wingo-bingo I am in business. However, when measuring the currency value, I can't obtain the unique currency from the records and this results in duplicated data which causes my current values to be 10x what they actually should be.

       

      Save for flattening the data using concantenation within the database views, is there any way to get just the value of the currency value to sum up correctly without the replication skewing the numbers?

        • 1. Re: One to Many Join Causing Replication of Data
          Robert Morton

          Hi Benjamin,

          This is a great use case for Data Blending in Tableau. Consider making two separate data sources that are each connected to a single table, and blend them together in your visualization. You can control the link level of detail by clicking the link icon in the Data window. Since Tableau will only join the two result sets after aggregating from each data source, you won't have the measure double-counting problem that you experience with a native join.

          -Robert

          • 2. Re: One to Many Join Causing Replication of Data

            Hi,

             

            I also have the same issue at my work.

            I tried using the tables as different data sources and blend the data for my use to avoid the duplication of data

            but the filters will not work across the data sources which is causing trouble.

            I have multiple worksheets from the data sources that I have and I want to use a filter that filters across all the sheets.

            And that filter cannot work out of that data source which is a drawback.

            Is there a way to fix this.

            Kindly help.


            Thanks & Regards,

            Raja

            • 3. Re: One to Many Join Causing Replication of Data

              Same problem for me!

               

              Any luck Raja?

               

               

              THanks,

              Franco