multiple dynamic checkbox จะ update แยกตามไอดี รายละเอียดด้านในครับ

<form id="form_item">
              <div class="row">
                <div class="col-lg-2">
                  <button type="button" class="btn btn-success" id="btn-save" data-loading-text="กำลังบันทึกข้อมูล..."><span class="glyphicon glyphicon-floppy-disk"></span> บันทึก</button>
                  <a type="button" class="btn btn-info" id="btn-signature" href="signature?Action=Yes&id=<?php echo $_GET['id']; ?>" style="display: none;"><span class="glyphicon glyphicon-edit"></span> ลงนาม</a>
                  <input type="hidden" name="id" id="id" value="<?php echo $_GET['id']; ?>">
                </div>
              </div>
              <br>
              <div class="row">
              <?php  
              $select_item = explode(',', $_GET['item']);
              $amount = explode(',', $_GET['amount']);
              $number = count($select_item);  
        // echo $select_item[0] ."<br>";
        // echo $select_item[1] ."<br>";

        try {
          for($i=0; $i<$number; $i++){ 
            if ($select_item[$i] == 1) {
               $name = 'Computer PC';
            }
            elseif ($select_item[$i] == 2) {
               $name = 'Notebook';
            }
            elseif ($select_item[$i] == 3) {
               $name = 'Microsoft Surface3';
            }
            else{
               $name = 'Apple iPad';
            }
    
            $status = 'idle';
            $sql_item = $db->prepare('SELECT list,machine_id 
                          FROM tbl_machine 
                          WHERE type = :type 
                            AND status = :status
                          ORDER BY machine_id ASC');
            $sql_item->bindParam(':type',$select_item[$i],PDO::PARAM_INT);
            $sql_item->bindParam(':status',$status,PDO::PARAM_STR);
            $sql_item->execute();
            echo '<div class="col-md-3">';
            // echo '<input type="hidden" id="hidden'.$amount[$i].'" value="'.$select_item[$i].'">';

            if ($sql_item->rowCount() > 1) {
                echo "<strong>".$name."</strong>";
                $x = 0;
              while ($results = $sql_item->fetch(PDO::FETCH_ASSOC)) {
                echo '<div class="checkbox">';
                echo  '<label>';
                  echo  '<input type="checkbox" class="item" name="item[]" id="item'.$results["list"].'" data-id="'.$amount[$i].'" data-sel="'.$select_item[$i].'" value="'.$results["machine_id"].'" />'.$results["list"];
                  echo  '</label>';
                  echo '</div>';
                  $x++;
              }
            }
            else {
              echo '<strong>ไม่มีข้อมูลหรือไม่มีเครื่องว่าง</strong>';
            }
            echo "</div>"; //col-md-3
          } //for
        }//try
          catch(PDOException $e) {
            echo 'ERROR: ' . $e->getMessage();
          } 
            ?>
            </div>
            </form>
          </div>

<?php
include 'connect.php';

if(is_array($_POST["item"])){
	$item = implode(',', $_POST['item']); //xx,xx,xx,xx
}
print_r($_POST['item']);
$id = $_POST['id']; //log_id
$machine_id = $_POST['item'];
try {
			$update = $db->prepare('UPDATE tbl_borrow_logs
									SET item = :item
									WHERE log_id = :id');
			$update->bindParam(':id',$id,PDO::PARAM_STR);
			$update->bindParam(':item',$item,PDO::PARAM_STR);
			$update->execute();

			// $update = $db->prepare('UPDATE tbl_select_item
			// 						SET machine = :item
			// 						WHERE id = :id');
			// $update->bindParam(':id',$id,PDO::PARAM_STR);
			// $update->bindParam(':item',$item,PDO::PARAM_STR);
			// $update->execute();

			$x = count($machine_id);
			$status = 'busy';
			for($i=0; $i < $x; $i++){
				$sql1 = $db->prepare('UPDATE tbl_machine 
									  SET status = :status 
									  WHERE machine_id = :id');
				$sql1->bindParam(':id',$machine_id[$i],PDO::PARAM_INT);
				$sql1->bindParam(':status',$status,PDO::PARAM_STR);
				$sql1->execute();
		}	
		echo "success";
	}
	
catch(Exception $e) {
    	//echo "Error: " . $e->getMessage();
    	echo 'Exception -> ';
    	var_dump($e->getMessage());
    }

$db = null;
?>