title: datetime to timestamp
body: <blockquote>
    <p><strong>Possible Duplicates:</strong><br>
    <a href="https://stackoverflow.com/questions/5895519/inverse-date-function-not-strtotime">Inverse date function? - not strtotime</a><br>
    <a href="https://stackoverflow.com/questions/5749319/is-it-possible-to-get-unix-time-from-such-date-2011-02-27-020446">Is it possible to get UNIX time from such date 2011-02-27 02:04:46?</a>  </p>
  </blockquote>
  
  
  
  <p>hello,</p>
  
  <p>we have this function to convert a timestamp to datetime:</p>
  
  <pre class="lang-php prettyprint-override"><code>$datetime = date('Y-m-d H:i:s', $timestamp);
  </code></pre>
  
  <p>is there a function to do the opposite?</p>
  
  <p>datetime to timestamp.</p>
  
  <p>Thanks</p>