Magento: find potential unused product attributes

unused.php

<?php

/**
 * MAGENTO_ROOT_DIR/unused.php
 * php -f unused.php
 */

$mageFilename = 'app/Mage.php';
if (!file_exists($mageFilename)) {
    echo $mageFilename." was not found";
    exit;
}
require_once $mageFilename;

// Bootstrap Magento
Mage::app('admin');

set_time_limit(0);
ini_set('display_errors', 1);

$product            = Mage::getModel('catalog/product');
$attributesByTable  = $product->getResource()->loadAllAttributes($product)->getAttributesByTable();
$adapter            = Mage::getResourceSingleton('core/resource')->getReadConnection();

foreach ($attributesByTable as $table => $attributes) {
    foreach ($attributes as $attribute) {
        $sql = "SELECT `value`, COUNT(*) AS `count` FROM `$table` WHERE `attribute_id` = " . $attribute->getAttributeId() . " GROUP BY `value`";
        $rows = $adapter->fetchAll($sql);
        if (count($rows) >= 0 && count($rows) <= 2) {
            var_dump($attribute->getAttributeCode(), $rows);
        }
    }
}

Hi mate, thanks for your work! I'm using your base to build a module here https://github.com/borasocom-team/Magento-AttributeCleaner .

At https://gist.github.com/jreinke/10023002#file-unused-php-L30 : i think there is a bug. If there is only value associated, the array has two elements. Please see this:

A better condition should be:

if( count($rows) === 1 && $rows[0]["value"] === null ) {

Am I wrong?

I ended up doing it like this: https://github.com/borasocom-team/Magento-AttributeCleaner/blob/0092895c603bcc38dfb2515054bc24b34cb7004d/src/app/code/community/Boraso/AttributeCleaner/Helper/Data.php#L147 Feedback is very welcome

Just in case someone else runs into this... I think the correct if test would be -

    if(( count($rows) === 1 && $rows[0]["value"] === null )|| (count($rows) === 0)){

You are looking for attributes that only have null for a value or has no no rows in the attribute table.