protected function _createIdListFromSql($sSql)
    {
        $rs = \OxidEsales\Eshop\Core\DatabaseProvider::getDb(\OxidEsales\Eshop\Core\DatabaseProvider::FETCH_MODE_ASSOC)->select($sSql);
        if ($rs != false && $rs->count() > 0) {
            while (!$rs->EOF) {
                $rs->fields = array_change_key_case($rs->fields, CASE_LOWER);
                $this[$rs->fields['oxid']] = $rs->fields['oxid']; //only the oxid
                $rs->fetchRow();
            }
        }
    }