ถามเรื่องการ select ครับ รบกวนด้วยครับ ผมจะจอย 3 ตาราง ผมต้องการทำหน้าที่เอาไว้ดู order การสั่งซื้อครับ แต่ผมเลือก select ไม่ถูกอะครับ

<td width="194" align="center" bgcolor="#666666">หมายเลขใบสั่งซื้อ</td> // order join member
<td width="129" align="center" bgcolor="#666666">วันที่สั่งซื้อ</td> // order join member
<td width="107" align="center" bgcolor="#666666">รหัสสินค้า</td> //orderdetail join product
<td width="120" align="center" bgcolor="#666666">ชื่อสินค้า</td> // orderdetail join product
<td width="84" align="center" bgcolor="#666666">ราคา</td> // orderdetail join product
<td width="89" align="center" bgcolor="#666666">จำนวน</td> // orderdetail join product
<td width="107" align="center" bgcolor="#666666">ราคารวม</td> //function(ราคา * จำนวน)
<td width="45" align="center" bgcolor="#666666">ผู้ซื้อ</td> // order join member
<td width="108" align="center" bgcolor="#666666">ชำระเงิน</td> // order join member

<?
session_start();
require("connect.php");
connectdb("orderdb");
mysql_query("set charset tis620");
$strSQL = "select * from member where Memid = '".$_SESSION['Memid']."' ";
$objQuery = mysql_query($strSQL);
$objResult = mysql_fetch_array($objQuery);
$Memid = $objResult['Memid'];
	date_default_timezone_set('Asia/bangkok');
	$day = date("d/m/Y H:i:s");
	$strSQL = "insert into orders (Orderdate,Status,Memid) values ('$day',1,'$Memid') ";
	$objQuery = mysql_query($strSQL);
	$strOrderid = mysql_insert_id();
	for($i=0;$i<=(int)$_SESSION["intLine"];$i++)
	{
		if($_SESSION["strPid"][$i] != "")
		{
			$strSQL = "insert into orderdetail (Orderid,Pid,Qty,Total) values ('".$strOrderid."','".$_SESSION["strPid"][$i]."','".$_SESSION["strQty"][$i]."','".$_SESSION["strTotal"][$i]."')";
			$objQuery = mysql_query($strSQL);
		}
	}
	session_destroy();
	?>
    <script>
    	alert("Success");
    	window.location="main.php";
		</script>

 <?php

if(!isset($_SESSION["intLine"]))
{
	echo "Cart Empty";
	exit();
}

$serverName = "localhost";
$userName = "root";
$userPassword = "root";
$dbName = "orderdb";
$objCon = mysqli_connect($serverName,$userName,$userPassword,$dbName);

if (!$objCon) {
    echo $objCon->connect_error;
    exit();
}
?>
  <form action="update.php" method="post">
<table width="1161" height="206"  border="1">
  <tr>
    <td width="173" height="65" align="center" bgcolor="#333333">รุปภาพ</td>
    <td width="173" height="65" align="center" bgcolor="#333333">รหัสสินค้า</td>
    <td width="403" align="center" bgcolor="#333333">ชื่อสินค้า</td>
    <td width="118" align="center" bgcolor="#333333">ราคา</td>
    <td width="176" align="center" bgcolor="#333333">จำนวน</td>
    <td width="105" align="center" bgcolor="#333333">ทั้งหมด</td>
    <td width="146" align="center" bgcolor="#333333">ลบสินค้า</td>
  </tr>
  <?php
  $Total = 0;
  $SumTotal = 0;

  for($i=0;$i<=(int)$_SESSION["intLine"];$i++)
  {
	  if($_SESSION["strPid"][$i] != "")
	  {
		$strSQL = "SELECT * FROM product WHERE Pid = '".$_SESSION["strPid"][$i]."' ";
		$objQuery = mysqli_query($objCon,$strSQL);
		$objResult = $objResult = mysqli_fetch_array($objQuery,MYSQLI_ASSOC);
		$Total = $_SESSION["strQty"][$i] * $objResult["Price"];
		$SumTotal = $SumTotal + $Total;
	  ?>
	  <tr>
      <td align="center" valign="middle" bgcolor="#FFFFFF"><img src="<? echo $objResult["Pic"];?>"width="120" height="110"/></td>
		<td align="center" valign="middle" bgcolor="#333333"><? echo $_SESSION["strPid"][$i];?></td>
		<td align="center" valign="middle" bgcolor="#333333"><? echo $objResult["Pname"];?></td>
		<td align="center" valign="middle" bgcolor="#333333"><? echo $objResult["Price"];?></td>
		<td align="center" valign="middle" bgcolor="#333333">
			<select name="txtQty<?php echo $i;?>">
				<?php 
			
				for($qty=1;$qty<=10;$qty++)
			  {
					$sel = "";
					if($_SESSION["strQty"][$i] == $qty)
				  {
						$sel = "selected";
				  }
			  ?>
				<option value="<?php echo $qty;?>" <?php echo $sel;?>><?php echo $qty;?></option>
				<?php
			  }
			  ?>
			</select>
		</td>
		<td align="center" valign="middle" bgcolor="#333333"><?=number_format($Total,2);?></td>
		<td align="center" valign="middle" bgcolor="#333333"><a href="deletecart.php?Line=<?=$i;?>"><img src="Picweb/pic admin/delete.png" width="40" height="40" /></a></td>
	  </tr>
	  <?php
	  }
  }
  ?>
</table>
<br>
<table width="400"  border="0">
  <tr>
  <td><input type="submit" value="Update"></td>
  <td align="right">Sum Total <?php echo number_format($SumTotal,2);?></td>
  </tr>
  </table>
</form>
<br><a href="main.php">Go to Product</a>
<?php
	if($SumTotal > 0)
	{
?>
	| <a href="addorder.php">ยืนยันการสั่งซื้อ</a>
<?php
	}
?>
<?php
mysqli_close($objCon);
?>

$Total = $_SESSION["strQty"][$i] * $objResult["Price"];
$_SESSION["strTotal"][$i] = $Total;

$strSQL = "SELECT * FROM product WHERE Pid = '".$_SESSION["strPid"][$i]."' ";