title: How to update datetime by +15 hours with MySQL
body: <p>I have a table containing a datetime column.</p>
  
  <p>I need to add 15 hours to all these values.</p>
  
  <p>e.g.</p>
  
  <pre><code>As Is: 2007-08-22 08:55:10  
  To Be: 2007-08-22 23:55:10
  
  As Is: 2009-08-22 14:55:10  
  To Be: 2009-08-23 05:55:10
  </code></pre>
  
  <p>Is there a MySQL <code>UPDATE</code> query that can do this?</p>