QUERY's not working correctly

PunkGo

hello...for some reaosn whenever i ask my query to do someting, like update or insert...it like doubles it...like if i ask to up date a user's points -2 it will do it -4 ...then when i want to insert something else...it will insert it twice into a row...is this a fixable error?heres my code for the UPDATE...

mysql_query("UPDATE users SET points=$user_points - $costofitem WHERE username='$auth_user'");

now my first thought was ok. np...i just pressed 4....but ived asked to echo the $costofitem and it says 2....
then heres my insert

mysql_query("INSERT INTO inventory (owner, item_id, item_name) VALUES ('$auth_user', '$wanteditem', '$item_name1')");

thanks for ur help.
heres the full code of it...

$wanteditem = $_GET['item'];
$wanteditem1 = $wanteditem;
$result_user = mysql_query("SELECT * FROM users WHERE username='$auth_user'");
$user_info = mysql_fetch_array($result_user);
$user_points = $_SESSION['user_points'];
$resultitem = mysql_query("SELECT * FROM items WHERE item_id='$wanteditem'");
$item_info = mysql_fetch_array($resultitem);
$costofitem = $item_info['item_cost'];
mysql_query("UPDATE users SET points=$user_points - $costofitem WHERE username='$auth_user'");
mysql_query("INSERT INTO inventory (owner, item_id, item_name) VALUES ('$auth_user', '$wanteditem', '$item_name1')");

i jus copied/pasted those codes from my script...so their not rlly in order..

guytoon

Actually if I understand in the right way :
$user_points = 10;
$costofitem = 2

the result of your query UPDATE $user_point-$costofitem = 6 !

Well that is an amazing result.

Are your sure that your query isn't called twice ? Try echo of your query just before it.
Try then your query diretly in mysql to see the result.
I don't think it can be the parentheses but try : UPDATE users SET points=($user_points - $costofitem) WHERE username='$auth_user' ;

Another choice : pray god !

simply___skewed

I've seen this behavior before and unfortunately - it was a code error 🙁

Although I don't necesarrily see it in what you've provided - perhaps you can check if it is called twice. Tracing would be your best option. try making print statements at everystep of your query and then print out your query - you could always copy paste your query into an sql editor or run it against your DB directly (PHPmyadmin - MYSQL) and see what happens - that should give you a very clear indication of exactly whats happening. Long and monotonous maybe - but effective.

Cheers