title: rounding down on varchar input
body: <p>I was making some SQL calculations and found a very strange behavior.
  When i <code>ROUND</code> the result of 2 fields it was rounded Down instead of UP.</p>
  
  <p>I checked the data types .. one is <code>double</code> and one is <code>varchar</code> (don't ask).<br>
  Never the less the behavior is strange I don't find a logical reason for it:</p>
  
  <pre><code>select ROUND(3.17 *  450 , 2); /* = 1426.50 */
  select ROUND(3.17 * '450', 2); /* = 1426.50 */
  
  select ROUND(3.17 *  450 ); /* = 1427 */
  select ROUND(3.17 * '450'); /* = 1426 !? */
  </code></pre>
  
  <p>The order of the params does not play a role.<br>
  Any idea what is the problem ?</p>