รวกวนช่อยดู code ดึงข้อมูลมาแสดงา ผิดตรงไหนมันฟ้องขึ้นว่า Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource

<?php
$sql = "Select * From employee Order by date Desc;";
$result = mysql_query($sql);
if(mysql_num_rows($result) != 0){
while ($dbarr = mysql_fetch_array($result))
{
echo "<table border = 1>";
echo "<tr>";
echo "<td><b>ชื่อ : </b></td>";
echo"<td>$dbarr[emp_id]</td>";
echo"</tr>";
echo"</table><p>";
}
}
?>

<?php
while ($dbarr = mysql_fetch_array($result, MYSQL_ASSOC))
{
echo "<table border = 1>";
echo "<tr>";
echo "<td><b>ชื่อ : </b></td>";
echo"<td>$dbarr[emp_id]</td>";
echo"</tr>";
echo"</table><p>";
}
?>