MySQL resource

Ok.... this is irritating. Essentially, my code (in a class) is doing this : $result = mysql_query($query, $this->connection); if ($result) { echo (mysql_num_rows($result)); } The way I read the manual, the if() only fires off if the query is executed, and then by definition mysql_num_rows() should contain at least a 0. So why do I get this error? Warning: Supplied argument is not a valid MySQL result resource in C:\blah\class_test.inc on line 195 If I echo($result) it comes back as 1 djo