private function query($sql) {
		if ($sth = $this->DB->query($sql)) {
			$res = $sth->fetchAll(PDO::FETCH_COLUMN);
		} else {
			$res = false;
		}
		return $res;
	}
private function query($sql) {
		if ($sth = $this->DB->query($sql)) {
			$res = $sth->fetchAll(PDO::FETCH_COLUMN);
		} else {
			$res = false;
		}
		return $res;
	}
private function query ( $ sql ) { if ( $ sth = $ this -> DB -> query ( $ sql ) ) { $ res = $ sth -> fetchAll ( PDO :: FETCH_COLUMN ) ; } else { $ res = false ; } return $ res ; }
DB query and fetchAll

@param string $sql
@return boolean|array
DB query and fetchAll