private static function dedupAndJoinShortTitles($seedKeyword) { if (empty($seedKeyword)) { return null; } $res = LDao::getUniqueShortTitlesForASeed($seedKeyword); if (!res || empty($res)) { return null; } $shortTitles = array(); foreach ($res as $dbRow) { $shortTitle = $dbRow->short_title; if (empty($shortTitle)) { continue; } $shortTitles[] = $shortTitle; } return implode(self::DEDUP_QUERY_DELIMITER, array_unique($shortTitles)); }