protected function _prepareWhereQuery($aWhere, $sSql)
    {
        $sSql = parent::_prepareWhereQuery($aWhere, $sSql);

        $sArtTable = getViewName('oxarticles', $this->_iEditLang);
        $sArtTitleField = "{$sArtTable}.oxtitle";

        // if searching in article title field, updating sql for this case
        if ($this->_aWhere[$sArtTitleField]) {
            $sSqlForTitle = " (CONCAT( {$sArtTable}.oxtitle, if(isnull(oxparentarticles.oxtitle), '', oxparentarticles.oxtitle), {$sArtTable}.oxvarselect)) ";
            $sSql = getStr()->preg_replace("/{$sArtTable}\.oxtitle\s+like/", "$sSqlForTitle like", $sSql);
        }

        return $sSql;
    }