code: private function getDisplayItems(): ?array 
      {
          /** squelch the sql warning in case of ill-formed filter field and catch the exception instead in order to alert the administrator of mistake. note, ideally any value that causes a query failure will be invalidated in the controller, but this is an extra measure of avoiding an unhandled exception while still logging/displaying the alert */
          if (null !== $filterColumnsInfo = $this->getFilterColumnsInfo()) {
              try {
                  $displayItems = @$this->mapper->select(null, $filterColumnsInfo);
              } catch (QueryFailureException $e) {
                  $this->events->insertError(EVENT_LIST_VIEW_FILTER_QUERY_FAIL, ['error' => $e->getMessage()]);
                  SlimPostgres::setAdminNotice('Query Failed', 'failure');
              }
          } else {
              $displayItems = $this->mapper->select();
          }
  
          return $displayItems;
      }
docs: get display items (array of recordset) from the mapper. special handling when filtering