How to correctly work out two include on the page?

Question

PHP

The page is not completely displayed with two active include's.
There are two inclusions.
One displays statistics on the book and the other video tutorials on it.
With deactivation (commented out) of one include, the second one works fine (and vice versa) displaying the entire index page entirely.

<?php

require 'db.php';

 $query = "select * from unch_statistic;";
 $statistics = db::getInstance()->get_result($query);
?>

<div class="container">
  <div class="row">
    <?php foreach ($statistics as $statistic): ?>
     <div class="col-lg-3 col-md-6">
 	     <div class="single-counter">
        <h1 class="counter"><?=$statistic['counter'];?></h1>
        <p><?=$statistic['name'];?></p>                                
      </div> 
     </div>
     <?php endforeach; ?>
  </div>
</div>

Similarly, I choose video lessons

Answer 1

Now fix to require_once 'db.php';
And start learning the normal approach.
model - controller - view