title: php - One Hour Earlier Than Given Datetime
body: <p>I'm having a problem here..</p>
  
  <p>Supposed I have this kind of datetime.</p>
  
  <pre>
  <code>
  $date = strtotime($date);
  </code>
  </pre>
  
  <p>I need this to be converted into the Unix-timestamp format but one hour earlier..I tried </p>
  
  <pre>
  <code>
  $date = strtotime($date-86400)
  </code>
  </pre>
  
  <p>, but seemed to me it is wrong. It returned 0 when I sneaked into the table. </p>
  
  <p>What is the appropriate way to achieve this?</p>
  
  <p>Thanks.</p>