Add value to a user not logged in using php - php

Question

I have a table (users) with various users. if you refer someone to register it creates a referal id in a field (refcode) similar to your (id) in his/her profile. now when he/she is logged in, i want to add value to the referal's profile.
So basically i need to add value to a user not logged in.
here is my code.
$sql="SELECT * FROM users";
$val=(2);
$result=mysql_query($sql,$bd);
$data=mysql_fetch_assoc($result);
while ($array = mysql_fetch_array($result)) {
// equate the value to a variable to use outside
// this while loop
$acc_balance = $array['com_balance'];
$comm = $array {$_SESSION['refcode']};
$commision = $array['id'];
}
$remainder = $acc_balance + $val;
$update_query = mysql_query("UPDATE users SET com_balance = '". mysql_real_escape_string($remainder) ."'
WHERE id=refcode");
if ($update_query) {
print ""

Answer 1

A bunch of changes, marked by numbers:
$sql="SELECT * FROM users where userID='$_SESSION['refcode']'"; //#1
$val = 2; //#2 : Why do u need the ()?
$result = mysql_query($sql,$bd);
$data=mysql_fetch_assoc($result);
while ($array = mysql_fetch_array($result)) {
// equate the value to a variable to use outside
// this while loop
$acc_balance = $array['com_balance'];
$comm = $array{$_SESSION['refcode']}; //#3: I am not sure what you're doing here?
$commision = $array['id'];
}
$remainder = $acc_balance + $val;
$update_query = mysql_query("UPDATE users SET com_balance = '". mysql_real_escape_string($remainder) ."'
WHERE id=refcode"); // #4: where are you defining refcode? if variable, the query needs to be WHERE id='$refcode'");
if ($update_query) {
print "Update successful";

Answer 2

Firstly, change:
$sql="SELECT * FROM users";
as you do not need to loop through an entire table just to get the details of the user logged in. Something like this should do the trick:
$yourID=3;// Assume this is sanitized data from a cookie or a login script.
$sql="SELECT * FROM users where userID=$yourID";
Secondly, when you verify the login of the user who referred the next user, just add in a query like this:
$update_query = mysql_query("
UPDATE users SET
com_balance = (select * from (
select com_balance from users where id=$yourID))");
This will update the new user with the balance from the referring user (which seems to be what you want). You will need to use the double subquery to get past the annoying mysql bug/feature where it cannot update a table from a subquery on the same table unless you encapsulate it in a second subquery.