mysql_affected_rows() don't work

Hi,
I have this problem:
My custom code is

$db =& JFactory::getDBO();
$query = "UPDATE `MY_TABLE` SET `MY_FIELD` = 'Si' WHERE `MY_TABLE`.`FIELD` = '$VAR'";
$db->setQuery($query);
$db->query();  

and it work right.
But if I add this

if(mysql_affected_rows() => 1)
{
 echo 'OK';
}
else
 {
  echo 'NO!';
}

it don't work.

Everyone can help me?

Thanks

Hi pierpari,

You need to check the Joomla! code and check the value from the $db object. It's probably something like $db->numRows() but I'm far from certain about that.

Bob

I find and try this:
$db->affectedRows();
but don't' work. The problem is that if i add everything to the first code it don't update.
Do you understand?
This work

$db =& JFactory::getDBO();
$query = "UPDATE `MY_TABLE` SET `MY_FIELD` = 'Si' WHERE `MY_TABLE`.`FIELD` = '$VAR'";
$db->setQuery($query);
$db->query();  

If I add just this, it don't work (don't print "OK" and don't update table

echo "OK";

Why?