You want to see in a Union node which data sources return no results for a query. How do you achieve this?

The Empty Union Behavior property is specifically designed to manage how a Union node functions when some of its data sources do not return any results. By configuring this property, you can adjust the behavior of the Union node to allow for better visibility into which data sources are yielding empty results.

When the Empty Union Behavior property is enabled and correctly set up, the system can signify which data sources have returned no results. This is particularly useful in scenarios where understanding the contributions of each data source is critical, such as in data quality assessments or when trying to debug data pipelines.

Other approaches may not provide the same level of relevant feedback regarding empty results. For instance, creating a union pruning configuration table or a standard union may involve differing methodologies that do not directly address the need to highlight the absence of results from specific data sources. Setting the is Null property in the Manage Mapping dialog pertains more to data validation purposes rather than tracking query results. Therefore, utilizing the Empty Union Behavior property serves as the most effective approach for achieving the desired outcome regarding visibility into empty result sets from data sources in a Union node.