Filter from Secondary Data Source Excludes Non-Matching Values

Published: 01 Jun 2018
Last Modified Date: 14 Oct 2019


When adding a filter from a secondary data source, then values that are present in the primary data source but are NULL or missing from the secondary data source will also be filtered out. This behavior appears as if the blend is acting as an INNER ad-hoc join rather than a LEFT ad-hoc join.


  • Tableau Desktop
  • Data Blending


Check the Include Null Values box in the Filter dialog


Discrete filters will have an option for NULL is the list of options, but the value NULL is not a part of any range of non-NULL numbers. Therefore the option to include NULL values is separate in continuous filters. By default NULL data is excluded from the filter.
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