title: mysql now() Incorrect datetime value for column - error code 1292
body: <p>When doing simple maths using now() ...</p>
  
  <pre><code>    mysql&gt; 
  select cdrstatuschangets from cdrs where ( cdrstatuschangets &lt; now() - 10 );
      +---------------------+
      | cdrstatuschangets   |
      +---------------------+
      | 2009-09-25 13:55:50 |
      +---------------------+
      1 row in set (0.00 sec)
  
      show warnings;
      Empty set (0.00 sec)
  </code></pre>
  
  <p>it often worked, but sometimes, ...</p>
  
  <pre><code>    mysql&gt; 
  select cdrstatuschangets from cdrs where ( cdrstatuschangets &lt; now() - 50 );
      +---------------------+
      | cdrstatuschangets   |
      +---------------------+
      | 2009-09-25 13:55:50 |
      +---------------------+
      1 row in set, 1 warning (0.00 sec)
  
  
  show warnings;
  +---------+------+-----------------------------------------------------------------------+
  | Level   | Code | Message |                                                                                  |
  +---------+------+-----------------------------------------------------------------------+
  | Warning | 1292 | Incorrect datetime value: '20090925211564.000000' for column 'cdrStatusChangeTS' at row 1 |
  +---------+------+-----------------------------------------------------------------------+
  1 row in set (0.00 sec)
  </code></pre>
  
  <p>and sometimes wouldn't give selection results despite being expected.</p>