Which keyword is used to merge query results in a core data services (CDS) view?

In the context of core data services (CDS) views, the keyword that facilitates the merging of query results is UNION. This keyword allows you to combine the results of two or more select queries into a single result set. Using UNION ensures that duplicate rows are removed, providing a distinct set of records from the combined queries.

When working with CDS, it's essential to understand that while JOIN is used to combine rows from two or more tables based on a related column, and CONCATENATE typically refers to string operations, they do not serve the purpose of merging result sets from separate queries the way UNION does. MERGE is not a standard SQL or CDS keyword for combining query results.

Union operations are particularly useful when you need to aggregate data that shares a similar structure from separate sources into a unified output, making UNION the correct choice for this scenario.