title: How to escape strings in pdo?
body: <p>I would like to know how to escape strings in pdo .
  I have been escaping the springs like in the code bellow but now with pdo I do not know how to do it </p>
  
  <pre><code>$username=(isset($_POST['username']))? trim($_POST['username']): '';
  $previlage =(isset($_GET['previlage']));
  $query ="SELECT * FROM site_user 
  WHERE username = '".mysql_real_escape_string($_SESSION['username'])."' AND  previlage ='Admin'";
  $security = mysql_query($query)or die (mysql_error($con));
  $count = mysql_num_rows($security);
  </code></pre>