The dashboard needs a single result with three slices at once: event counts by event type, event counts by user, and the grand total over all events. Running three queries and stitching them via union is ugly and inefficient: a single query with grouping over multiple sets of columns handles it. Show the event type, the user id, and the count of events — for the «by type only», «by user only», and «grand total» slices. Sort by event type (empty values last), then by user id (empty values last too).