Undefined Variable in PHP

[Minnow]

I'm working towards sending an XML request to a URL using cURL in PHP.First I just wanted to make sure my request is sending the right data so here is a snippet from my code. I will add the curl statements in later once I know i'm sending the right data.here is my code so far:\[code\]$format = 'Y-m-j G:i:s'; $date = date ( $format );$d = date ( $format, strtotime ( '-90 days' ) );$sql = mysql_query("SELECT * FROM recurringPayments WHERE lastpmt <= '$d'");$num_rows = mysql_num_rows($sql); echo $num_rows . " results found";echo "<table style=\"border:1px solid green;\"> <tr bgcolor=\"#bdd73b\"> <th>ID</th> <th>Company Name</th> <th>Annual Subscription</th> <th>Package</th> <th>Cost</th> <th>Payer Ref</th> <th>Payment Ref</th> <th>Last Payment Date</th> </tr>"; while ($row = mysql_fetch_array($sql)) { echo "<tr>"; echo "<td>" . $row['ID'] . "</td>"; echo "<td>" . $row['compName'] . "</td>"; echo "<td>" . $row['annualSub'] . "</td>"; echo "<td>" . $row['package'] . "</td>"; echo "<td>" . $row['cost'] . "</td>"; echo "<td>" . $row['payerref'] . "</td>"; echo "<td>" . $row['pmtref'] . "</td>"; echo "<td>" . $row['lastpmt'] . "</td>"; } echo "</table>"; while ($row = mysql_fetch_array($sql)){$xml_data ='http://stackoverflow.com/questions/3907475/<request type="receipt-in" timestamp="20030520151742">'. '<merchantid>test</merchantid>'. '<account>internet</account>'. '<orderid>transaction01</orderid>'. '<amount currency="EUR">'.$row['cost'].'</amount>'. '<payerref>'.$row['payerref'].'</payerref>'. '<paymentmethod>'.$row['pmtref'].'</paymentmethod>'. '<autosettle flag="1" />'. '<md5hash />'. '<sha1hash>c81377ac77b6c0a8ca4152e00cc173d01c3d98eb</sha1hash'. '</request>';} echo $xml_data;\[/code\]When I try to echo $xml_data, I get the following error message:\[quote\] Notice: Undefined variable: xml_data in C:\wamp\www\Internal\paymentDue.php on line 63\[/quote\]It was my logic that I would be able to output the XML as I output the table, however I could be (probably am) wrong. Any guidance is appreciated.Thanks.PS:I also just realise while I'm posting this, that if I use the while loop in the current context, $xml_data will be overwritten each time it loops. Any help with this would be great too.