/**
  * Search articles by catgories without start articles
  * @param array $aCategories
  * @param int $iOffset
  * @param int $iNumOfRows
  * @param string $sResultType element of {article_id, object}
  *
  * @return array of articles
  */
 function findMatchingContentByCategories($aCategories = array(), $iOffset = 0, $iNumOfRows = 0, $sResultType = '')
 {
     for ($i = 0; $i < count($aCategories); $i++) {
         if (!is_int((int) $aCategories[$i]) or !$aCategories[$i] > 0) {
             return array();
         }
     }
     $sql = $this->_buildQuery_MatchingContentByCategories($aCategories, $iOffset, $iNumOfRows);
     $this->db->query($sql);
     $aResult = array();
     while ($oRow = $this->db->getResultObject()) {
         if ($sResultType == 'article_language_id') {
             $aResult[] = $oRow->idartlang;
         } else {
             $aResult[] = $oRow;
         }
     }
     return $aResult;
 }