title: Ruby datetime suitable for mysql comparison
body: <p>Rails has been good with automatically inserting correctly formatted datetimes in MySql without the need for me to give it much thought. </p>
  
  <p>However, for doing a validation, I need to check if a stored mysql datetime value (ie 2008-07-02 18:00:00) is greater than or less than "now". I can call <code>DateTime.now</code> or <code>Time.now</code> but how can I convert that into the format mysql likes?</p>
  
  <p>Thanks</p>