สอบถามปัญหาคำสั่ง insert into มันไม่เข้าในฐานข้อมูล ต้องเขียนอย่างไรค่ะ

<?php 	require_once("../includes/template.php") ;    require_once("../includes/function.php") ; 
require_once("includes/shopping_function.php");	
show_header("บันทึกรายการสั่งซื้อ") ;   show_menu() ; 	check_authen("member") ;	  

if ( !empty( $_POST["btnNext"] ) ) { 
	if ( empty($_POST["txtName"]) || empty($_POST["txtSurname"]) || empty($_POST["txtAddress"]) || empty($_POST["txtDistrict"]) || $_POST["selProvince"] == "0" || empty($_POST["txtZipcode"]) ) {
		process_message( "กรอกข้อมูลไม่ครบ", "shopping_process2.php" ) ;	
	
	} else {  	
		$dblink = connect_db() ;  
		$now = date( "y-m-d h:i:s" ) ;
		$ship_name = $_POST["txtName"] . "  " . $_POST["txtSurname"] ; 
		$ship_address = $_POST["txtAddress"] . " เขต/อำเภอ " . $_POST["txtDistrict"] . "  จังหวัด " . $_POST["selProvince"]."  รหัสไปรษณีย์ " . $_POST["txtZipcode"] ; 
		$insert = "INSERT INTO tblOrders (mUserName, oDateTime, oShipName, oShipAddress, oShipping, oStatus, oBill) VALUES ('" . $_SESSION["ssMember"] . "', '" . $now . "', '" . $ship_name . "', '" . $ship_address . "', '" . $_POST["hShip"] . "', 1, '" . $_POST["rdoBill"] . "') " ;
		$resultSql = mysqli_query( $dblink, $insert ) ;
		$affected = mysqli_affected_rows( $dblink ) ;  	
		$orderid = mysqli_insert_id( $dblink ) ;
		
		if ( $affected == 1 ) { 
			$arrItems = explode( "|", $_SESSION["cart"] ) ; 
			$arrQuality = explode( "|", $_SESSION["quality"] ) ;   
			
			for ( $i = 0 ; $i < count( $arrItems ) ; $i++ ) {
				$sqlPB = " SELECT pbID FROM tblPromotionBook WHERE bISBN='".$arrItems[$i]."' AND ExpireDate IS NULL" ;
				$resultPB = mysqli_query( $dblink, $sqlPB ) ;
				$rowsPB = mysqli_num_rows( $resultPB ) ;   
				if ( $rowsPB > 0 ) {
					$rowsPB = mysqli_fetch_array( $resultPB, MYSQL_ASSOC ) ;
					$insertItems = "INSERT INTO tblOrderItems (orderID, bISBN, pbID, oiQuantity) VALUES ( '" . $orderid."', '" . $arrItems[$i] . "', '" . $rowsPB["pbID"] . "', " . $arrQuality[$i] . ") " ;
				} else {
					$insertItems = "INSERT INTO tblOrderItems (orderID, bISBN, oiQuantity) VALUES ( '" . $orderid."', '" . $arrItems[$i] . "', " . $arrQuality[$i] . ") " ;
				}
				
				$resultSql = mysqli_query( $dblink, $insertItems ) ;
			}
			
			unset( $_SESSION["cart"] ) ;
			unset( $_SESSION["quality"] ) ;
			unset( $_SESSION["Shipping"] ) ;

			$msg = "บันทึกรายการสั่งซื้อเรียบร้อยแล้ว" ;			
			process_message( $msg, "print_orderReport.php?oid=".$orderid ) ;
			
		}
		mysqli_close( $dblink ) ;
	}
}

show_footer() ;  ?>