ช่วยแก้ error คำสั่ง insert เข้าดาต้าเบส ให้หน่อยค่ะ

$num_inv = count($inv_id);
	if($num_inv > 0){
	   $arr_inv = array_values ($inv_id);   
	   $id = "";
       for($i=0; $i<$num_inv; $i++){
		 $update_tax = "update room set Arri_val ='".$Arrival[$arr_inv[$i]]."', Price_S ='".$PriceS[$arr_inv[$i]]."' where No = '".$arr_inv[$i]."'";
		 
		 //echo "update room set Arri_val ='".$Arrival[$arr_inv[$i]]."', Price_S ='".$PriceS[$arr_inv[$i]]."' where No = '".$arr_inv[$i]."'";
		 mysql_query($update_tax);
         $id .= $arr_inv[$i];
		  if($i != ($num_inv -1)){ $id .= ",";};
	   }
	}
	   
	    if($id != ''){
          $billstr = "BP".date("ym"); 
		  $check_suffix = mysql_query("select CHECKIN_ID from checkin where CHECKIN_ID like '".$billstr."%' order by CHECKIN_ID desc limit 1")  or die (mysql_error());
		  $num = mysql_fetch_row($check_suffix);
		  $strnum = explode("-",$num[0]);
		  $lastdigit = explode("00",$strnum[1]);
		  $credit = $_POST["credit"];
		  $autonum = $lastdigit[1]+1;
		  $bill_no = $billstr."-00".$autonum;
		  
		  mysql_query("update room set Status = '2', cus_id = '$cusno', bill_no = '$bill_no' where No in (".$id.")") or die (mysql_error()); 
         $getdate = explode(" ",$chdate);
	     $date_ =$getdate[0];
         $time = $getdate[1];
		 
          $strSQL = "INSERT INTO checkin ";
          $strSQL .="(Bill_no, Date, Time, Cus_ID, Receipt, Food_cp1, Food_cp2, Food_cp3,Internet_c1, Price_in1, Internet_c2, Price_in2, Internet_c3, Price_in3, Internet_c4, Price_in4, Internet_c5, Price_in5,)";
          $strSQL .="VALUES ";
          $strSQL .="('".$bill_no."','".$date_."','".$time."','".$cusno."','".$Receipt."','".$food_coupons1."','".$food_coupons2."','".$food_coupons3."','".$internet_card1."','".$price_in1."','".$internet_card2."','".$price_in2."','".$internet_card3."','".$price_in3."','".$internet_card4."','".$price_in4."','".$internet_card5."','".$price_in5."'); ";
          mysql_query($strSQL) or die (mysql_error());
		  
	}

   $checkinlist = mysql_query("select * from room where bill_no = '".$bill_no."'") or die (mysql_error());