ช่วยเช็คให้ผมหน่อยคับ ผมใช้ mysql_num_rows มันไม่มีค่า

<?
session_start();
	$username = $_POST["user_login"];
	$pwd = $_POST["pwd_login"];
	include ("connect.php");
	mysql_select_db($dbname);
	$sql = "SELECT * FROM employee where user_name='" . $username ."' and employee_id='" . $pwd ."'";
	
	$result = mysql_query($sql) or die ("Error in query");
	

	if(mysql_num_rows($result) > 0){
		$row = mysql_fetch_array($result);
		$_SESSION["user_name"] = $row["user_name"];
		echo "<META HTTP-EQUIV=Refresh CONTENT='1; URL=test.php'>";
	}
	else{
		echo "<META HTTP-EQUIV=Refresh CONTENT='1; URL=form_login.php'>";
	}
?>
<meta http-equiv="Content-Type" content="text/html; charset=windows-874">