Need help! Simple counter

I'm trying to make a simple counter. I want to make it so if a user clicks '+1' it adds 1 to the counter. If the user clicks '-1' it subtracts 1 from the counter. The data is stored in a MySQL database. Here is what I have so far, it isn't working!:

<?php if (isset($_POST['id']) && isset($_POST['count'])) {
		$passed_id = (int)$_POST['id'];
		$passed_count = (int)($_POST['count']);
		$getcount = "SELECT count FROM table WHERE id='" . $passed_id . "'";
		$oldcount = mysql_query($getcount);
		$newcount = $oldcount + $passed_count;
		$update_count = "UPDATE table SET count='" . $newcount . "' WHERE id='" . $passed_id . "'";
		mysql_query($update_count) or die('Error, failed to update count.');
}?>

<form method="post" action="index.php">
<center><input type="submit" class="text_button" name="count" value="-1"/>
<input type="submit" class="text_button" name="count" value="1"/>
<input type="hidden" name="id" value="<?=$row['id']?>"/>
</form>
</html>

Code (markup):

I'm not sure whats wrong. Any help is greatly appreciated. Thanks in advance! NOTE: My database is properly figured and is accessible (its just not shown), so that isn't the problem.

 

What I would do first is echo out your variables to make sure that they are all being passed. Then start tracing your code from there.

 

I seem to have spotted the problem, the $passed_id echos out as "Resource id #6". This messes everything up. What did I write wrong in regards to $passed_id?

 

try changing your code from:

$passed_id = (int)$_POST['id'];

Code (markup):

to:

$passed_id = int($_POST['id']);

Code (markup):

and do the same with the other variables.

More Info

 

That ended up making it worse and made it stop working completely. Thanks for trying to help though. I'm still trying to figure this out..

EDIT: I think the ID is working ok actually. Its the $oldcount = mysql_query($getcount); that isn't working.

 

Im not sure about this, but isn't count a reserved word for mysql? I am not sure but I think using count as a column name for your table is a good idea... try changing the column name for that and see if it helps.. I had problems before where I named a column in my database as desc, which is a reserved word for mysql..

 

<?php
if (isSet($_POST['id']) && is_numeric($_POST['id']) && isSet($_POST['count']))
{
    $passed_id    = $_POST['id'];
    $passed_count = ($_POST['count']);
    $getcount = "SELECT `count`
                 FROM table
                 WHERE id = '" . $passed_id . "'";
    $query = mysql_query($getcount);
    $items = mysql_num_rows($query);
    
    if ($items > 0)
    {
        list($oldcount) = mysql_fetch_array($query);

        $newcount = $oldcount + $passed_count;
        $update_count = "UPDATE table
                         SET count = '" . $newcount . "'
                         WHERE id  = '" . $passed_id . "'";
        mysql_query($update_count) or die('Error, failed to update count.');
    }
    
    /*
     OR YOU COULD DO if your $_POST['count'] contains similair things like this (-1), (+1)
    */
    
    $cnt = ($_POST['count'] < 0) ? "-1" : "+1";
    $update_count = "UPDATE table
                     SET count = count " . $cnt . "'
                     WHERE id  = '" . $_POST['id'] . "'";
    mysql_query($update_count) or die('Error, failed to update count.');
}
?>

<form method="post" action="index.php">
<center><input type="submit" class="text_button" name="count" value="-1"/>
<input type="submit" class="text_button" name="count" value="1"/>
<input type="hidden" name="id" value="<?=$row['id']?>"/>
</form>
</html>

Code (markup):

Please try to maintain a good looking way of writing your scripts, like my example, you can see 1 one view what's happening...

Hopefully you understand what i've changed... if not, look under here

the COUNT word is an reserved mysql word, if you like to use it add `(tilde) to it `count`
if your input is a number please check it with is_numeric
I've changed your MySQL query style (easier to read)
use mysql_num_rows to check if you had any results
extract with list an variabel from an array (with you see being loaded from MySQL)
mysql_fetch_array for reading output of mysql

More questions? please ask

 

I hope everything works out for you using EricBruggema advice. But note that (int)var is the wrong way to use the int() function.

 

Thanks a lot, that code worked out!

Thanks, I'll take note of that.

 

You can bypass a lot of this if you don't need the old count value - just increment it directly in mysql and save the extra call:

<?php
if (isset($_POST['id']) && isset($_POST['count'])) 
{
  $passed_id = (int)($_POST['id']);
  $passed_count = (int)($_POST['count']);
  $update_count = "UPDATE table SET count=count+($passed_count) WHERE id='$passed_id' LIMIT 1"
  mysql_query($update_count) or die('Error, failed to update count.');
}
?>

PHP:

(I like adding the LIMIT clause 'just in case')

Besides saving one mysql call, you do what is called an atomic (all at once) update - in the first code, if anyone called an update from when you read the counter to when you wrote the update back, you could have invalid values.