ปัญหา การ เพิ่ม ลบ แก้ไขข้อมูลในฐานข้อมูล ไม่สำเร็จ!!

   <?php
include("connDB.php");
$result = mysql_query("select * from listfood WHERE listfood_id LIKE '1000%' order by listfood_id");

while($dbarr = mysql_fetch_array($result)) {
?>
  <tr>
    <td width="5%" bgcolor="#CCCCFF" align="center"><?php echo $dbarr['listfood_id'] ; ?></td>
    <td width="20%" bgcolor="#CCCCFF" align="center"><?php echo $dbarr['listfood_name'] ; ?></td>
    <td width="5%" bgcolor="#CCCCFF" align="center"><center><a href="100001edit.php?id=<?=$dbarr['listfood_id'];?>">แก้ไข</a></center></td>
    <td width="5%" bgcolor="#CCCCFF" align="center"><center><a href="100001delete.php?id=<?=$dbarr['listfood_id'];?>" OnClick="return Conf(this)">ลบ</a></center></td>
  </tr>
  </td>
<?php
}
?>

  <form action="100001add_in.php" method="post" onSubmit="return checkform(this);">
    <p>&nbsp;</p>
    <table width="490" border="1">
      <tr>
        <td colspan="2" align="center" bgcolor="#CC0000"><label><span class="style11">เพิ่มรายการอาหาร</span></label></td>
        </tr>
      <tr>
        <td width="111" align="center"><strong>รหัสอาหาร</strong></td>
        <td width="369"><label>
          <input name="listfood_id" type="text" size="30" style="width: 150px" maxlength="8">
        </label></td>
      </tr>
      <tr>
        <td align="center"><strong>รายการอาหาร</strong></td>
        <td><label>
          <input name="listfood_name" type="text" size="30" style="width: 150px" maxlength="80">
        </label></td>
      </tr>
      <tr>
        <td colspan="2" align="center"><label></label>
          <input type="submit" name="submit" id="submit" value="บันทึก">         
         <input name="cancle" type="submit" id="cancle" value="ยกเลิก"></td>
        </tr>
    </table>
      </form>

<?php 
include("connDB.php");

$listfood_id = $_POST['listfood_id'];
$listfood_name = $_POST['listfood_name'];

$result = mysql_query("INSERT INTO listfood (listfood_id,listfood_name)
                                            VALUES ('$listfood_id','$listfood_name')");
if($result) {
echo "<center>เพิ่มข้อมูลสำเร็จ<br><br><< <a  href=\"index1.php\">ตกลง</a> >></center>";
}
else
{
echo "<center>เพิ่มข้อมูลไม่สำเร็จ<br><br><< <a  href=\"index1.php\">ตกลง</a> >></center>";
}

?>

<?php
include "connDB.php";

$listfood_id = $_GET['listfood_id'];
$listfood_name=$_GET['listfood_name'];

$result = mysql_query("select * from listfood where listfood_id='$listfood_id'");
$dbarr = mysql_fetch_array($result) ;

?>

<?php
include "connDB.php";

$listfood_id = $_POST['listfood_id'];
$listfood_name = $_POST['listfood_name'];

$sql="UPDATE  listfood_id='$listfood_id' , listfood_name='$listfood_name' WHERE listfood_id = '$listfood_id'";
$result = mysql_query($sql);

if($result) {
echo "<center>
<table border=\"1\" >
  <tr>
    <center>
   แก้ไขข้อมูลสำเร็จ<br><br>
    <font size=\"4\"><a href=\"index.php\">กลับหน้าหลัก</a></font>
    </center>    
    </td>
  </tr>
</table>
</center>";
}
else {
echo "<center>
<table border=\"1\">
  <tr>
    <td height=\"136\" bgcolor=\"#FFCCFF\">
    <center>
 การแก้ไขข้อมูลล้มเหลว !!<br><br>
    <font size=\"4\"><a href=\"100001edit.php\">กลับ</a></font>
    </center>    
    </td>
  </tr>
</table>
</center>";
}

?>

<?
include "connDB.php";

$listfood_id = $_GET['listfood_id'];
$sql = "delete from listfood where listfood_id=$listfood_id";
$result = mysql_query($sql);

if($result) {
echo "<center>
<table border=\"1\" >
  <tr>
    <td height=\"136\">
    <center>
    ลบข้อมูลเรียบร้อยแล้ว <br><br>
    <font size=\"4\"><a href=\"100001show.php\">ตกลง</a></font>
    </center>    
    </td>
  </tr>
</table>
</center>";
}
else {
echo "<center>
<table border=\"1\" >
  <tr>
    <td height=\"136\" bgcolor=\"#FFCCFF\">
    <center>
    <font size=\"5\" color=\"#000080\">การลบล้มเหลว !!</font><br><br>
    <font size=\"4\"><a href=\"100001show.php\">กลับ</a></font>
    </center>    
    </td>
  </tr>
</table>
</center>";
}

?>
 <a href="food_database.php?id=<?=$dbarr['listfood_id'];?>">เรียกดูข้อมูลในฐานข้อมูล</a></center>