title: MySQL greater than with microtime timestamp
body: <p>I have one PHP script inserting rows in a MySQL database. Each row has a field 'created_at' which is filled with the value of the PHP function microtime(true), and inserted as a double. (microtime because I need something more precise than to the second)</p>
  
  <p>I have another PHP script that selects rows based on that created_at field.</p>
  
  <p>When I go ahead and select like this:
  <code>SELECT * FROM `ms_voltage` WHERE created_at &gt; 1302775523.51878</code>
  I receive a resultset with, as the first row, the row with <strong>exactly that value</strong> for created_at.</p>
  
  <p>This occurs from within my PHP script and from within PhpMyAdmin when manually doing the query. But not always, not for every value. Just once and a while really.</p>
  
  <p>How is this possible? I didn't ask for greater than/equals, I want strictly greater than.
  Am I overlooking something type-related perhaps?</p>