Wordpress Custom Cat SQL Query

<?php

            $post_cat = $category->taxonomy; // This will equal a custom category type.
            $post_term = $category->term_id; // This will equal the page's category id.
                // Sets the global $wpdb
                global $wpdb;
                // Starts the db query
                $query = "
                SELECT DISTINCT ID, guid, post_parent FROM $wpdb->term_taxonomy, $wpdb->terms, $wpdb->posts p where p.post_type = 'attachment'
                                AND p.post_mime_type LIKE 'image/%'
                                AND p.post_status = 'inherit'
                                AND p.post_parent IN
                                        (SELECT object_id FROM $wpdb->term_relationships WHERE term_taxonomy_id = $post_term)
                                AND $wpdb->term_taxonomy.taxonomy = '$post_cat'
                                AND $wpdb->terms.term_id = $post_term
                ";

            $results =  $wpdb->get_results( $query );

            if ( $results ) {
            shuffle($results);
                    foreach ( (array) $results as $image ) {
                        $url = get_attachment_link($image->post_parent);
                        $thumb = wp_get_attachment_image( $image->ID, 'thumbnail', false );
                        $alt = get_post_meta($image->ID, '_wp_attachment_image_alt', true);
                        echo '<li style="display:inline-block;"><a href="' . get_permalink($image->post_parent) .'">' . $thumb . '</a></li>'."\n";
                    }
                }
        ?>