Some basic summary behavior that doesn't need to be repeated as much as code that goes into summaryQuery()
public function summaryBasics($count_field = TRUE) {
// Add the number of nodes counter
$distinct = $this->view->display_handler
->getOption('distinct') && empty($this->query->no_distinct);
$count_alias = $this->query
->addField($this->view->storage
->get('base_table'), $this->view->storage
->get('base_field'), 'num_records', array(
'count' => TRUE,
'distinct' => $distinct,
));
$this->query
->addGroupBy($this->name_alias);
if ($count_field) {
$this->query
->set_count_field($this->tableAlias, $this->realField);
}
$this->count_alias = $count_alias;
}