โค้ด select ตาราง ไม่แสดงผล ค่ะ ไม่ทราบว่าจะเขียน sql อย่างไรดี งง

$sql="Select id, st_id , stautus,classid, company.cname  From  training INNER JOIN company ON training.c_id = company.c_id where status = 1";
//echo $sql;
$db_query=mysql_db_query($db,$sql);
$num_rows=mysql_num_rows($db_query);
//echo $num_rows;
?>
</p>
<table width="55%" border="0" align= "center" cellpadding="1" cellspacing="1">
  <tr>
    <td width = "9%" height="33" align = "center" bgcolor="#66CCFF"><span class="style6"> รหัส </span></td>
     <td width = "25%" align = "center" bgcolor="#66CCFF"><span class="style6">รหัสนักศึกษา  </span></td>
	 <td width = "30%" align = "center" bgcolor="#66CCFF"><span class="style6">สถานประกอบการ  </span></td>
	 	 <td width = "24%" align = "center" bgcolor="#66CCFF"><span class="style6">ชั้นปี  </span></td>

  </tr>
</table>
<?
	$a=0;
	while($a<$num_rows)
	{
	$result = mysql_fetch_array($db_query);
$id=$result[id];
$st_id=$result[st_id];
$c_id=$result[c_id];
$classid=$result[classid];
$status=$result[status];

?>
<table width = "55%" height="22" border ="0" align="center" cellpadding="1" cellspacing="1">
  <tr>
    <td width ="9%" align = "center" bgcolor="#66FFFF"><span class="style7"><? echo "$id";?></span></td>    

    <td width ="25%" align = "left" bgcolor="#66FFFF"><a href="<? echo "detshow.php?idcode=$id"; ?>"><? echo "$st_id";?></td>
	    <td width ="30%" align = "left" bgcolor="#66FFFF"><? echo "$c_id";?></td>
		    <td width ="24%" align = "right" bgcolor="#66FFFF">ปริญญาตรี <? echo "$classid";?>  ปี		    </td>


  </tr>
</table>
<?
		$a++;
	}
	
	mysql_close();
?>