While the SQL compiler tries to make the most efficient use of data as specified by the query, sometimes the author of the query knows more about some aspect of the stored data than is evident to the compiler. In this case, the author can make use of the query plan to modify the original query to provide more information or more guidance to the query compiler.
Jim Coutcher, Senior Director/Principal, Global Head of Enriched Studies, Real World Solutions, IQVIA Qi Li, Physician Executive, InterSystems Matt Stannard, life Sciences Advisor, InterSystems