Description:
------------
mysql version is 5.1.45-community
when I use the script below,$result->num_rows return 0;(it is supported to return 1;I echo the sql,and execute it in mysql client,and return 1 result)
if I change sql to "select `id` from mobile_breed",$result->num_rows return the right numbers

Test script:
---------------
<?php
function getBreedId($breed_name,$handle)
{
	$handle = new mysqli("localhost","root","123456","wjtx");
	$sql = "select `id` from mobile_breed where `breed_name`='".$breed_name."' limit 0,1";
	$result = $handle->query($sql);
	if(!$result)
	{
		return false;
	}
	else
	{
                $num = $result->num_rows();
		if($num==0)
		{
			return false;
		}
		else
		{
			$row = $result->fetch_assoc();
			return $row['id'];
		}
	}
}
echo getBreedId("nokia",'5230');
?>

Expected result:
----------------
return an id;

Actual result:
--------------
return false;
because $result->num_rows return 0,so returned fasle;