function dataBaseConnect(){
            $dbuser = 'xx';
            $dbpassword = 'xxx';
            try {
                $this->handler = new PDO('mysql:host=localhost;dbname=x', $dbuser, $dbpassword);
                $this->handler->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
            } catch (PDOException $err) {
                echo $err->getMessage();
                die();
            }
        }
function getTimeValue(){
        //$this->start= "SELECT `start_time` FROM `table_ex` WHERE id=(SELECT MAX(id) FROM `table_ex`)";
        //$this->handler->exec($this->start);

        $sql = "SELECT `start_time` FROM `table_ex` WHERE id=(SELECT MAX(id) FROM `table_ex`)";
        $this->start = $this->handler->query($sql, PDO::FETCH_COLUMN, 0);
    }

function printVal(){
        //tak w skrócie jak chcę wykorzystać tę zmienną

        dataBaseConnect();
        getTimeValue();
        $this->messOuput = "Sth text " .$this->startTime;
}