PHP PDO problem with 2 tables

[CosminStan]

Hello,
I have a little problem. This is what I want to achive:
I have 2 mysql tables (categories, channels), the channel table has a cat_id in it. I want to update/edit a product and place it in another category but the code that I've made shows just one catedory (id=1) even if the product has a parent id of 5.

try {
        //prepare query
        $query = "select channel_id, name, category_id from channels where channel_id = ? limit 0,1";
        $stmt = $pdo->prepare( $query );
        //this is the first question mark
        $stmt->bindParam(1, $_REQUEST['id']);
        //execute our query
        $stmt->execute();
        //store retrieved row to a variable
        $row = $stmt->fetch(PDO::FETCH_ASSOC);
        //values to fill up our form
        $channel_id = $row['channel_id'];
        $name = $row['name'];
        $category_id = $row['category_id'];
}catch(PDOException $exception){ //to handle error
        echo "Error: " . $exception->getMessage();
}
$query2 = "SELECT * FROM categories";
$stmt2 = $pdo->prepare( $query2 );
$stmt2->execute();
$results = $stmt2->fetchAll(PDO::FETCH_ASSOC);
?>
<!--we have our html form here where new user information will be entered-->
<form action='#' method='post' border='0'>
    <table>
        <tr>
            <td>Channel Name</td>
            <td><input type='text' name='name' value='<?php echo $name;  ?>' /></td>
        </tr>
        <tr>
            <td>Category</td>
            <td>
            <?php foreach($results as $rows) {?>
            <select name="fileselect">
                <option name='cat_id' value=" <?php echo $rows['category_id']; ?>"> <?php echo $rows['name']; ?></option>
                <!-- <input type='text' name='category_id' value='<?php //echo $category_id;  ?>' /> -->
            <?php } ?>
            </select>
            </td>
        </tr>
        <tr>
            <td></td>
            <td>
                <!-- so that we could identify what record is to be updated -->
                <input type='hidden' name='channel_id' value='<?php echo $channel_id ?>' /> 
                <!-- we will set the action to edit -->
                <input type='hidden' name='action' value='update' />
                <input type='submit' value='Edit' />
            </td>
        </tr>
    </table>
</form>

The update parte is ommited as it works if there is no dropdown, just a plain text input.