My shopping cart doesn't add products correctly

[cstjuste]

Hi Everyone,

 

I've been working on this code for my shopping cart.  The problem is that when I try to update the cart with additional items, it adds the items but also gives me a couple of error messages.  For instance, if I have 1 of product A in my cart, and I want to have 3 instead of 1, it gives me a total of 4.

 

Product A - 1

Product A - 3

 

When I try to remove the the excess product, it removes both line items out of my cart.  I was trying to figure this out all day yesterday, but any help would be much appreciated. 

 

function showCart() {

global $db;

$cart = $_SESSION['cart'];

if ($cart) {

  $items = explode(',',$cart);

  $contents = array();

  foreach ($items as $item) {

  $contents[$item] = (isset($contents[$item])) ? $contents[$item] + 1 : 1;

  }

  $output[] = '<form action="cart.php?action=update" method="post" id="cart">';

  $output[] = '<table>';

  foreach ($contents as $id=>$qty) {

  $sql = 'SELECT * FROM apple WHERE id = '.$id;

  $result = $db->query($sql);

  $row = $result->fetch();

  extract($row, EXTR_PREFIX_SAME, 'ink');

  $output[] = '<tr>';

  $output[] = '<td><a href="cart.php?action=delete&id='.$id.'" class="r">Remove</a></td>';

  $output[] = '<td>'.$lip.' '.$printerT.'</td>';

  $output[] = '<td><input type="text" name="qty" value="'.$qty.'" size="3" maxlength="3" /></td>';

  $total += $qty;

  $output[] = '</tr>';

  }

  $output[] = '</table>';

  $output[] = '<p>Total Quantity: <strong>'.$total.'</strong></p>';

  $output[] = '<div><button type="submit">Update cart</button></div>';

  $output[] = '</form>';

} else {

  $output[] = '<p>You shopping cart is empty.</p>';

}

return join('',$output);

}

 

and here is the function that calls the query

  /**

    * Returns an instance of MySQLResult to fetch rows with

    * @param $sql string the database query to run

    * @return MySQLResult

    * @access public

    */

    function query($sql) {

        if (!$queryResource=mysql_query($sql,$this->dbConn))

            trigger_error ('Query failed: '.mysql_error($this->dbConn).

                          ' SQL: '.$sql);

        return new MySQLResult($this,$queryResource);

    }

}

and here is the fetch function

/**

    * Fetches a row from the result

    * @return array

    * @access public

    */

    function fetch () {

        if ( $row=mysql_fetch_array($this->query,MYSQL_ASSOC) ) {

            return $row;

        } else if ( $this->size() > 0 ) {

            mysql_data_seek($this->query,0);

            return false;

        } else {

            return false;

        }

    }

 

 

Notice: Query failed: 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 SQL: SELECT * FROM apple WHERE id = in /home/waldon/public_html/inc/mysql.class.php on line 109

 

Warning: mysql_fetch_array(): supplied argument is not a valid MySQL result resource in /home/waldon/public_html/inc/mysql.class.php on line 151

 

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/waldon/public_html/inc/mysql.class.php on line 167

 

Warning: extract() [function.extract]: First argument should be an array in /home/waldon/public_html/inc/functions.inc.php on line 29

[p2grace]

I would start by verifying the contents of the $contents array.  The query fails because $id is empty, which means the contents of the array aren't correct.