code: protected function prepareQuery()
      {
          if (false === $this->isQueryPrepared) {
              $options = array(
                  SelectorSourceInterface::RESULT => SelectorSourceInterface::RESULT_IDENTIFIERS,
                  SelectorSourceInterface::LIMIT => $this->limit,
                  SelectorSourceInterface::OFFSET => $this->offset,
                  SelectorSourceInterface::ORDERBY => $this->orderBy,
                  SelectorSourceInterface::GROUPBY => $this->groupBy,
              );
              $this->setIdsArray(
                  $this->source->loadIds(
                      $this->criterias,
                      array_merge($this->options, $options)
                  ),
                  array_merge($this->options, $options)
              );
              $this->isQueryPrepared = true;
          }
  
          return $this;
      }
docs: prepare ids : there the criterias are fetched
  @throws Exception\NoDataException
  @return \Yucca\Component\Selector\SelectorAbstract