title: Force user to logout session PHP
body: <p>I can't seem to find a straightforward answer to this question. Is there a way in which I can force a logged in user to logout? My login system essentially just relies on a session containing the user's unique ID (which is stored in a mysql database). So essentially just...</p>
  
  <pre><code>if (isset($_SESSION['user_id'])) {
  echo "You're logged in!";
  } else {
  echo "You need to login!";
  }
  </code></pre>
  
  <p>But let's say I want to ban this user, well I can change their status to banned in my database but this won't do anything until the user logs out and attempts to log back in... So, how do I force this user to logout? Preferably without checking every single time they view a page whether or not their status has been switched to "banned" because that seems like unnecessary stress on my server. Any help is appreciated, thank you.</p>