Вы можете использовать этот пример
<?php
$resulte = mysqli_query($connection, "select DISTINCT senderid from chatting where senderid!=3 OR receiverid =3 UNION select DISTINCT receiverid from chatting where senderid=3 OR receiverid !=3 ORDER BY senderid desc limit 0,10");
$rowe = mysqli_fetch_array($resulte);
if (!$resulte) {die("Error: Data not found..");}
else{
...loop
}