title: phpMyAdmin event error #1542 interval too big
body: <p>I have an MySQL event that deletes any rows older than 1 month. I now want to change that so it deletes rows older than 6 months (it cleans up a database for messages sent in a game).</p>
  
  <p>My (edited) MySQL event is:</p>
  
  <pre><code>DELETE FROM messages WHERE date &lt; (NOW() - INTERVAL 6 MONTH)
  </code></pre>
  
  <p>The error I get is:</p>
  
  <pre><code>The following query has failed: "CREATE DEFINER=`admin`@`localhost` EVENT `delete msgs` ON SCHEDULE EVERY 0 DAY_HOUR STARTS '2013-07-19 18:00:00' ON COMPLETION PRESERVE ENABLE DO DELETE FROM messages WHERE date &amp;lt; (NOW() - INTERVAL 6 MONTH)"
  MySQL said: #1542 - INTERVAL is either not positive or too big
  </code></pre>
  
  <p>The event functions fine but I can't even save it as it is now. If I open the event and immediately save I get the same error.</p>