forum_home.php

<?php
  $db = new mysqli('localhost', 'root', 'password', 'local');

  if ($db->connect_errno)
  {
  }
  else
  {
    echo '<table>';
    $req = $db->query('SELECT * FROM section');

    foreach ($req as $sec)
    {
      $req2 = $db->query('SELECT t.* FROM topics AS t WHERE t.id_section = ' . $sec['id']);

      // ligne de la section
      echo '<tr class="section">';
      echo '<td>' . $sec['name'] . '</td>';
      echo '</tr>';

      foreach ($req2 as $top)
      {
        $req3 = $db->query('SELECT m.* FROM messages AS m, sujets AS s WHERE s.id_topic=' . $top['id'] . ' AND s.id=m.id_sujet ORDER BY m.post_date LIMIT 1');
        if ($req3)
          $msg = $req3->fetch_assoc();
        else
          $msg['content'] = "lol";

        echo '<tr class="topic">';
        echo '<td>' . $top['name'] . '</td>';
        echo '<td>' . $msg['content'] . '</td>';
        echo '</tr>';
      }
    }

    echo '</table>';
  }
?>