1064 when clicking paypal checkout button and not logged in as a user

Hello

This is an unusual problem, and probably doesn't belong here (apologies in advance),, I would like to ask if anyone could point me in the right direction.

My zencart has been customized, the original programmer MIA, trying to find problem myself, I have limited knowledge of php or sql, but learning.

When clicking on the Checkout with PAYPAL button (not logged in as a user) - I get an error page:

WARNING: An Error occurred, please refresh the page and try again.

Reading through these forums, I learned to check the error logs and here is what I have:

PHP Fatal error: 1064:You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1 :: select customers_whole from customers where customers_id = in /home3/kwmagicc/public_html/includes/classes/db/mysql/query_factory.php on line 120

I looked at that file and could not see the problem, not that I was expecting it to jump out and bite me, but I fear I am looking at the wrong file.

Now I assume it has something to do with the wholesale pricing module not coded correctly, but could use a little guidance as to where to check next.

Any help appreciated

Phil

tracking it down to a piece of custom code maybe - I can't see the problem:

/*------------------------------Whole sale customer code-------------------*/
$customer_whole_obj = $db->Execute('select `customers_whole` from `'.TABLE_CUSTOMERS.'` where `customers_id` ='.$_SESSION['customer_id']);
$customer_whole = $customer_whole_obj->fields['customers_whole'];
if($customer_whole == 4){
  $_SESSION['customer_level'] =4; 
	//print_r($_SESSION);
  if($_SESSION['payment'] == 'paypalwpp' || $_SESSION['payment'] =='cc'){
    $this->info['charges'] = 2.5;
    $this->info['total_without_charges'] = $this->info['total'];
    $this->info['charges_amt'] = ($this->info['total'] * $this->info['charges'])/100;
    $this->info['total'] = $this->info['total'] + $this->info['charges_amt'];
  }
}
/*------------------------------End Whole sale customer code-------------------*/

Try changing this:$customer_whole_obj = $db->Execute('select `customers_whole` from `'.TABLE_CUSTOMERS.'` where `customers_id` ='.$_SESSION['customer_id']);to this:```
$customer_whole_obj = $db->Execute('select customers_whole from '.TABLE_CUSTOMERS.' where customers_id ='.(int)$_SESSION['customer_id']);