Warning: mysql_num_rows() error for my uni project

[jamesyrawr]

I seem to get this error message when I run this

please can someone help?

 

Warning: mysql_num_rows() expects parameter 1 to be resource, boolean given in C:\wamp\www\unisite\products.php on line 11

I can't figure this out at all

<?php

    if(isset($_GET['action']) && $_GET['action'] == "add"){
        $id = intval($_GET['id']);
        if(isset($_SESSION['cart'][$id])){
            $_SESSION['cart'][$id]['quantity']++;
        } else {
            $sql2 = "SELECT * FROM products WHERE prod_id = [$id] ";
            $query2 = mysql_query($sql2);

            if(mysql_num_rows($query2) != 0){
                $row2 = mysql_fetch_array($query2);
                $_SESSION['cart'][$row2]['prod_id'] = array("quantity" =>1, "price" => $row2['price']);
            } else {
                $message = "This product id is invalid";
            }
        }
    }
?>
<h2 class="message"> <?php if(isset($message)){echo $message;}?> </h2>
<h1>Products page</h1>

<table>
    <tr>
        <th>Name</th>
        <th>Description</th>
        <th>Price</th>
        <th>Action</th>
    </tr>
    <?php
    $sql = "SELECT * FROM products ORDER BY name ASC";
    $query  = mysql_query($sql)or die(mysql_error());

    while($row = mysql_fetch_assoc($query)){
    ?>

    <tr>

        <td><?php echo $row['name']; ?> </td>

        <td><?php echo $row['prod_description']; ?> </td>

        <td>£<?php echo $row['prod_price']; ?> </td>

        <td><a href="index.php?page=products&action=add&id=<?php echo $row['id_prod']; ?>">add to cart</a></td>
    </tr>



<?php

/**
* @author James Bell
* @copyright 2010
*/

}

?>
</table>

[btherl]

Your query failed because the sql is invalid, so $query2 is the boolean value "false".  A simple way to check for errors is like this:

 

$query2 = mysql_query($sql2) or die("Query failed: $sql2\n": mysql_error());

 

To fix the query, try removing the [ and ] characters.

[jamesyrawr]

thanks for that

i had made an error in my coding and typed one of the field names differently too how it was in my database too.

 

but now im getting a new error in it

 

 

Notice: Undefined index: price in C:\wamp\www\unisite\products.php on line 13

 

<?php

    if(isset($_GET['action']) && $_GET['action'] == "add"){
        $id = intval($_GET['id']);
        if(isset($_SESSION['cart'][$id])){
            $_SESSION['cart'][$id]['quantity']++;
        } else {
            $sql2 = "SELECT * FROM products WHERE id_prod = $id ";
            $query2 = mysql_query($sql2);
            
            if(mysql_num_rows($query2) != 0){
                $row2 = mysql_fetch_array($query2);
                $_SESSION['cart'][$row2['id_prod']] = array("quantity" => 1, "price" => $row2['price']);
            } else {
                $message = "This product id is invalid";
            }
        }
    }
?>
<h2 class="message"> <?php if(isset($message)){echo $message;}?> </h2>
<h1>Products page</h1>

<table>
    <tr>
        <th>Name</th>
        <th>Description</th>
        <th>Price</th>
        <th>Action</th>
    </tr>
    <?php
    $sql = "SELECT * FROM products ORDER BY name ASC";
    $query  = mysql_query($sql)or die(mysql_error());
    
    while($row = mysql_fetch_assoc($query)){
    ?>
    
    <tr>
    
        <td><?php echo $row['name']; ?> </td>
        
        <td><?php echo $row['prod_description']; ?> </td>
        
        <td>£<?php echo $row['prod_price']; ?> </td>
        
        <td><a href="index.php?page=products&action=add&id=<?php echo $row['id_prod']; ?>">add to cart</a></td>
    </tr>



<?php

/**
* @author James Bell
* @copyright 2010
*/

}

?>
</table>>

 

 

[Anti-Moronic]

$row2['price'] doesn't exist or is empty. You can solve the problem by first ensuring the data is what you expect:

 

echo $row2['price']

 

..and then if necessary, declaring the variable:

 

$row2['price'] = '';

 

//note, that must happen prior to

 

$row2 = mysql_fetch_array($query2);