Difficulty in exporting XML from MySQL database via PHP using SimpleXML - php

Question

I'm a complete novice, and have been asked to finish a project for someone (much more knowledgeable than I) who has just left.
I currently have a MySQL database, which I am trying to export as an XML file. This is going fine, but unlike PHP, I can't combine two separate columns.
So where I have two entries - lat (latitude), and Lon (longitude) - in my MySQL database, I can't output them in XML as one entry.
In PHP I would simply write: $latlon = $lat.",".$lon;
But I cannot do so in the XML output below.
Does anyone know how I could write this to achieve the required result, of simply having two entries listed under one child?
function createxml($x) {
global $mysqli;
include('xml.php');
$sxe = new SimpleXMLElement($xmlstr);
//get mysql data
if ($result = $mysqli->query("SELECT id,county,main_page,lat,lon,volume,texty,pdf,thumb FROM texts3 ORDER BY id ASC LIMIT $x"))
{
//found volumes already in DB
while ($r = $result->fetch_array(MYSQLI_BOTH)) {
$record = $sxe->addChild('record');
$record->addChild('latitude', $r['lat']);
$record->addChild('longitude', $r['lon']);
$record->addChild('latlon', $r['']);
}
$result->close();
}

Answer 1

If you have the r array why don't you try:
while ($r = $result->fetch_array(MYSQLI_BOTH)) {
$record = $sxe->addChild('record');
$latlon = $r['lat'].",".$r['lon'];
$record->addChild('latitude', $r['lat']);
$record->addChild('longitude', $r['lon']);
$record->addChild('latlon', $latlon);
}