XML不显示结果

am following this tutorial https://developers.google.com/maps/documentation/javascript/adding-a-google-map

This is my xml file that is supposed to render the restaurants on the map

<?php
   require("phpsqlsearch_dbinfo.php");
   // Get parameters from URL
   $center_lat = (isset( $_GET["lat"] ) ? $_GET["lat"] : 1.1026 ); 
   $center_lng =( isset( $_GET["lng"] ) ? $_GET["lng"] : -37.0132 ); 
   $radius= ( isset( $_GET["radius"] ) ? $_GET["radius"] : 25 );

  //  $center_lat = $_GET["lat"];
  //  $center_lng = $_GET["lng"];
  //  $radius = $_GET["radius"];
   // Start XML file, create parent node
   $dom = new DOMDocument("1.0");
   $node = $dom->createElement("restaurants");
   $parnode = $dom->appendChild($node);
   // Opens a connection to a mySQL server
   $connection=mysqli_connect ("127.0.0.1", $username, $password);
   if (!$connection) {
     die("Not connected : " . mysqli_error($connection));
   }
   // Set the active mySQL database
   $db_selected = mysqli_select_db($connection,$database );
   if (!$db_selected) {
     die ("Can\'t use db : " . mysqli_error($connection));
   }
   // Search the rows in the restaurants table
   $query = sprintf("SELECT  physical_address,opening_time,closing_time,days_of_operation,website,email,phone, lng, lat, ( 3959 * acos( cos( radians('%s') ) * cos( radians( lat ) ) * cos( radians( lng ) - radians('%s') ) + sin( radians('%s') ) * sin( radians( lat ) ) ) ) AS distance FROM restaurants HAVING distance < '%s' ORDER BY distance LIMIT 0 , 20",
  mysqli_real_escape_string($connection,$center_lat),
  mysqli_real_escape_string($connection,$center_lng),
  mysqli_real_escape_string($connection,$center_lat),
  mysqli_real_escape_string($connection,$radius));

   $result = mysqli_query($connection,$query);
   $result = mysqli_query($connection,$query);
   if (!$result) {
     die("Invalid query: " .mysqli_error($connection));

   }

  echo @mysqli_fetch_assoc($result);
   while ($row = @mysqli_fetch_assoc($result)){

     $node = $dom->createElement("restaurant");
     $newnode = $parnode->appendChild($node);
     $newnode->setAttribute("name", $row['name']);
    //  $newnode->setAttribute("opening_time", $row['opening_time']);
    //  $newnode->setAttribute("closing_time", $row['closing_time']);
    //  $newnode->setAttribute("days_of_operation", $row['days_of_operation']);
    //  $newnode->setAttribute("physical_address", $row['physical_address']);
     $newnode->setAttribute("lat", $row['lat']);
     $newnode->setAttribute("lng", $row['lng']);
     $newnode->setAttribute("distance", $row['distance']);
   }

    // echo saveXML();

   echo $dom->saveXML();
   ?>

It doesnt produce any output enter image description here

The XML file should take data from the table on database and populate it on a map

The XML file does not output anything This is the phpsqlsearch_dbinfo.php file

<?php
$username="root";
$password="";
$database="tafuta_restaurant";
?>