ขอสอบถามหน่อยคับผม insert ไม่เข้าเลยครับไม่รู้ว่าผิดตรงไหน

<?php
session_start();
include('include/config.php');
include('include/function.php');
?>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<?php
if($_POST['action']=="adds_tag_durable")
{
	$tag_du_id = $_POST['tag_du_id'];
	$id = $_POST['id'];
	$tag_du_number = $_REQUEST['tag_du_number'];
	$tag_du_cost = $_REQUEST['tag_du_cost'];
	$work_du_id = $_REQUEST['work_du_id'];
	$tag_du_note = $_REQUEST['tag_du_note'];
    $tag_du_start = $_REQUEST['tag_du_start'];
    $tag_du_end	 = $_REQUEST['tag_du_end'];
    $tag_du_percen = $_REQUEST['tag_du_percen'];
    $tag_du_comment = $_REQUEST['tag_du_comment'];
   
	$sql  = mysql_query("insert into tag_work_durable  set id = '$id' , tag_du_number = '$tag_du_number' , tag_du_cost = '$tag_du_cost' , work_du_id = '$work_du_id' , tag_du_note = '$tag_du_note' , tag_du_start = '$tag_du_start' , tag_du_end = '$tag_du_end' , tag_du_percen = '$tag_du_percen' , tag_du_comment = '$tag_du_comment' ,last_update = now()");
   if($sql){
	$sql2  = mysql_query("insert into tag_work_durable_2  set id = '$id' , tag_du_number = '$tag_du_number' , tag_du_cost = '$tag_du_cost' , work_du_id = '$work_du_id' , tag_du_note = '$tag_du_note' , tag_du_start = '$tag_du_start' , tag_du_end = '$tag_du_end' , tag_du_percen = '$tag_du_percen' , tag_du_comment = '$tag_du_comment' ,last_update = now()");
	if ($sql2) {echo "";}
	 else {echo "ERROR: " . $sql . "<br>" . $conn->error;}
   } 
   else {echo "Error1: " . $sql . "<br>" . $conn->error;}

	exit("<script>alert('เพิ่มข้อมูลเรียบร้อยแล้ว');window.location=\"system_index_details_durable.php?id=$id\";</script>");
}
	
?>