<?php
include 'connection.php';
$sql = $dbh->prepare("select id,fullname from users");
$sql->execute();
while ($row = $sql->fetch()){
 $id = $row[0];
 $fullname = $row[1];
 echo $fullname.'<br>';
 //or it could equal $fullname = $row['fullname'];
 //or it could equal $id = $row['id'];

}
?>