$row = mysql_query("SELECT * FROM `calendar` WHERE `user_id`='$id_user'") or die(mysql_error());
$ilosc_rekordow=0;
while(4 > $ilosc_rekordow AND $row1 = mysql_fetch_array($row)) {
    echo 'id postu:'.$row1[id].'<br/>';
    echo 'temat:"'.$row1[topic].'"<br/>';
    echo 'treść:<br/>"'.$row1[text].'"';
}