Overrides Drupal\Core\Entity\DatabaseStorageController::buildQuery().
Overrides DatabaseStorageController::buildQuery
protected function buildQuery($ids, $revision_id = FALSE) {
$query = parent::buildQuery($ids, $revision_id);
// Specify additional fields from the user and node tables.
$query
->innerJoin('node', 'n', 'base.nid = n.nid');
$query
->addField('n', 'type', 'node_type');
$query
->innerJoin('users', 'u', 'base.uid = u.uid');
$query
->addField('u', 'name', 'registered_name');
$query
->fields('u', array(
'uid',
'signature',
'signature_format',
));
return $query;
}