title: Why are PHP's mysql_ functions deprecated?
body: <p><em>Playing Devil's Advocate a little here as I stopped using these functions a while ago, but the question is genuine and probably matters to a lot of SO users.</em></p>
  
  <p>We all know that using <code>mysql_</code> functions in the wrong way can be very dangerous, it can leave your website vulnerable, etc. but used correctly these functions can be protected against SQL injection and are <a href="http://we-love-php.blogspot.co.uk/2012/07/mysql-or-mysqli-or-pdo.html" rel="noreferrer">actually a fair bit faster</a> than the newer PDO functions.</p>
  
  <p>Bearing all this in mind, why have the <code>mysql_</code> functions been deprecated?</p>