How to inform that the query result zero rows?

Dear all,
I want to inform that the query return zero result? does anyone know how to revised my code so in case my query return zero result and it will echo "search result =0"

here is my the code, I have try it but still it doesn't inform that "search result =0" if the query return zero result. please revised it:

$today= date("Y-m-d");

$result = mysql_query("SELECT * FROM t_master_reg r, t_master_category c WHERE r.dt_reg_reminder <='$today' AND (r.dt_reg_end >='$today') AND r.id_category = c.id_category");

if (!$result) {echo"search result=0";}
else
{
			$x=1;
		while ($data = mysql_fetch_object($result)) 
		{ 
			echo"<tr>
			<td >$x<br></td>
			<td >$data->no_reg</td>
			<td >$data->category_name<br></td>
			<td >$data->reg_subject<br></td>
			<td >$data->dt_reg_end<br></td>
			<td >$data->reg_link</td>
			</tr>";
			
			$x++;
   
		}
}