header2.php

<?php
include 'db2.php';

$r=mysqli_query($con,"SELECT * FROM `notification_db` ORDER BY notification_id desc");

?>
<header class="app-header"><a class="app-header__logo" href="index.html">STMS</a>
      <!-- Sidebar toggle button--><a class="app-sidebar__toggle" href="#" data-toggle="sidebar" aria-label="Hide Sidebar"></a>
      <!-- Navbar Right Menu-->
      <ul class="app-nav">
        <li class="app-search">
          <input class="app-search__input" type="search" placeholder="Search">
          <button class="app-search__button"><i class="fa fa-search"></i></button>
        </li>
        <!--Notification Menu-->
        <li class="dropdown"><a class="app-nav__item" href="#" data-toggle="dropdown" aria-label="Show notifications"><i class="fa fa-bell-o fa-lg"></i></a>
          <ul class="app-notification dropdown-menu dropdown-menu-right">
            <div class="app-notification__content">
            <?php 
                $count=0;
                while ($blah = mysqli_fetch_assoc($r)) { $count++;   ?>  
            <li><a class="app-notification__item" href="javascript:;"><span class="app-notification__icon"><span class="fa-stack fa-lg"><i class="fa fa-circle fa-stack-2x text-primary"></i><i class="fa fa-envelope fa-stack-1x fa-inverse"></i></span></span>
                  <div>
                    <p class="app-notification__message"><?php echo $blah['content']; ?></p>
                    <?php  ?>
                    <p class="app-notification__meta"><?php echo $blah['time']; ?></p>
                  </div></a></li>
                  <?php } ?>
              </div>
            </div>
            <li class="app-notification__footer"><a href="stu_noti_view.php">See all notifications.</a></li>
          </ul>
        </li>
        <!-- User Menu-->
        <li class="dropdown"><a class="app-nav__item" href="#" data-toggle="dropdown" aria-label="Open Profile Menu"><i class="fa fa-user fa-lg"></i></a>
          <ul class="dropdown-menu settings-menu dropdown-menu-right">
            <li><a class="dropdown-item" href="logout.php"><i class="fa fa-sign-out fa-lg"></i> Logout</a></li>
          </ul>
        </li>
      </ul>
    </header>