Empty searches are a valid way to begin the query process before focusing results by applying filters. However, it should be noted that results will vary depending on the search fields selected in the Search Fields menu. When an empty search is performed, behind the scenes, the iSearch Analytics search engine is performing a Wildcard search in the selected search fields. This means the results returned will contain all records that have a value in the selected field(s).
Learn more about Search Fields.
Learn more about Search Syntax and how the iSearch Analytics search engine works.