2 Replies Latest reply on Mar 14, 2016 11:38 AM by Dan Cory

    using is_numeric to filter out non numeric values

    Katrina Roque



      I am attempting to create a simple histogram but am running into trouble with filtering out non-numeric values.  I am using a udf in my query to filter out non-numeric values from my data set and I've ran queries against our data base to verify if the udf works and it does. However it does not seem to work when I use it in Tableau.  This is the error I am receiving is below.  Does anyone have any suggestions as to


      1. efficient ways to filter out non numeric values?  The database I'm using is Redshift

      2. explain to me what this message is and any possible reasons why I am receiving it

      3. any additional suggestions on how I can create a histogram using millions of rows of data.  We get about 5-6 million rows of data a day.


        • 1. Re: using is_numeric to filter out non numeric values
          Yuriy Fal

          Hi Katrina,


          Couldn't give a definite answer without making some things clear:


          Q1. What exactly your UDF is doing?

          -- Filtering rows from a result set

          -- Replacing string values with something else (0, NULL)

          -- Something else


          Q2. Which way you're using your UDF in Tableau?

          -- as a Custom SQL when making a datasource

          -- as a Calculation using any of RAWSQL functions


          Q3. What data type Tableau shows

          for your field in question (named [value])?

          -- Numeric (Number decimal or Number whole)

          -- String


          Q4. Are you making an extract or connecting live

          to your Redshift instance?


          Q5. Your Tableau version number

          and your Redshift ODBC driver version number,


          Answering to my Q3 could help the most.





          • 2. Re: using is_numeric to filter out non numeric values
            Dan Cory

            This error message happens when something goes wrong creating an extract and probably has nothing to do with your UDF or Redshift. I would recommend upgrading to the latest maintenance release if you haven't already. If that still doesn't work, contact Tableau Support and send them your logs for investigation.