PHP: Fetching from database returns nothing, nor any errors - maybe path issue?

Question

From index.php I'm calling the function <?php displayTitle(7) ?> passing the id in order to get this record's title. The function doesn't return anything, nor do I get any errors. What am I missing here?

Any help would be greatly appreciated.

Folder structure:

index.php
|_includes/
  |_downloads/
  |  |_displayInfo.php
  |
  |_db.php

index.php

<?php include('includes/downloads/displayInfo.php'); ?>
<div><?php displayTitle(7) ?></div>

db.php

<?php
$DBServer = 'xxxx';
$DBUser   = 'xxxx';
$DBPass   = 'xxxx';
$DBName   = 'xxxx';
$DBtable  = 'db_name';

$conn = mysqli_connect($DBServer, $DBUser, $DBPass, $DBName);

// check connection
if ($conn->connect_error) {
    die('Error : ('. $conn->connect_errno .') '. $conn->connect_error);
}
?>

displayInfo.php

<?php 
require_once('../includes/db.php');
function displayTitle($id) {
    $sql = "SELECT title FROM " . $DBtable . " WHERE id = $id";
    $rs=$conn->query($sql);
    if($rs === false) {
      trigger_error('Wrong SQL: ' . $sql . ' Error: ' . $conn->error, E_USER_ERROR);
    } else {
      $arr = $rs->fetch_all(MYSQLI_ASSOC);
    }

    foreach($arr as $row) {
      $titles = $row['title'];
      echo $titles;
    }
}
?>

Database table:

CREATE TABLE IF NOT EXISTS `db_name` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `title` text CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
  `url` varchar(250) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL,
  `clicks` int(11) NOT NULL,
  `dates` date NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=11 ;