PHP Newbie - Bad at Math

[Anon]

I am trying to subtract from points_forwarded.
The problem is, the user inputs a Dollar amount into a form where one dollar = 250 points.
This form field is called cert_amount.

$sql = "UPDATE vipcustomer SET points_forwarded='$cert_amountr WHERE custid=$uid";
$result = mysql_query($sql);
$d=$cert_amount*250;
$cert_amountr=$points_forwarded-$d;
$d returns the correct amount for me.

But nothing else does, I get either 0 or 1 for a result in points_forwarded
Can somebody help me with this?

Thank You

[[deleted]]

error_checking is everything:

$sql = "UPDATE vipcustomer SET points_forwarded='$cert_amountr WHERE custid=$uid";

What is that single quote before $cert_amountr for?

[Anon]

$sql = "UPDATE vipcustomer SET points_forwarded='$cert_amountr WHERE custid=$uid";

is wrong so I removed the ' and now it will not change the database's amount for points_forwarded at all. It should read:

$sql = "UPDATE vipcustomer SET points_forwarded='$cert_amountr' WHERE custid=$uid";

Still the same result. I do now get the correct results for everything else. But the value always comes up 0.

$points_forwarded = number_format($points_forwarded);

was the evil code. . . but I still have my problem.

[[deleted]]

"and now it will not change the database's amount for points_forwarded at all."

so your points_forwarded column is not an integer??

what does your code look like now?