PHP and MySQL problem, Notice: Undefined index: id

Question

I come to see you because I have a problem in PHP, I'm a novice, I try to recover the ID but I can't get this error : "Notice: Undefined index: id in C:\xampp\htdocs\Dossier\Stage\admin\index.php on line 49"

Can you help me, please? Thank you.

<?php
   require 'database.php';
   $db = Database::connect();
   $statement = $db->query("SELECT people.name, people.society, people.email, people.city, people.direct_line, people.internal_number, people.phone_number, people.abbreviated_number,  people.service, business_service.name  AS service FROM people LEFT JOIN business_service ON people.service = business_service.id ORDER BY people.id DESC");
   while($item = $statement->fetch()) {
      echo '<tr>';
         echo '<td>' . $item['name'] . '</td>';
         echo '<td>' . $item['society'] . '</td>';
         echo '<td>' . $item['email'] . '</td>';
         echo '<td>' . $item['city'] . '</td>';
         echo '<td>' . $item['direct_line'] . '</td>';
         echo '<td>' . $item['internal_number'] . '</td>';
         echo '<td>' . $item['phone_number'] . '</td>';
         echo '<td>' . $item['abbreviated_number'] . '</td>';
         echo '<td>' . $item['service'] . '</td>';
         echo '<td width=300>';
            echo '<a class="btn btn-default" href="view.php?id=' . $item['id'] . '"><span class="glyphicon glyphicon-eye-open"></span> Voir</a>';
            echo '  ';
            echo '<a class="btn btn-primary" href="update.php?id=' . $item['id'] . '"><span class="glyphicon glyphicon-pencil"></span> Modifier</a>';
            echo '  ';
            echo '<a class="btn btn-danger" href="delete.php?id=' . $item['id'] . '"><span class="glyphicon glyphicon-remove"></span> Supp</a>';
         echo '</td>';
      echo '</tr>';
   }
?>