Permite que, en el buscador de WooCommerce, se puedan buscar pedidos por el SKU de los productos.

add_filter('woocommerce_shop_order_search_results', 'wc_search_order_by_sku', 9999, 3);

function wc_search_order_by_sku($order_ids, $term, $search_fields) {
    global $wpdb;
    if (!empty($search_fields)) {
        $product_id = wc_get_product_id_by_sku($wpdb - > esc_like(wc_clean($term)));
        if (!$product_id) return $order_ids;
        $order_ids = array_unique(
            $wpdb - > get_col(
                $wpdb - > prepare("SELECT order_id FROM {$wpdb->prefix}woocommerce_order_items WHERE order_item_id IN ( SELECT order_item_id FROM {$wpdb->prefix}woocommerce_order_itemmeta WHERE meta_key = '_product_id' AND meta_value = %d ) AND order_item_type = 'line_item'", $product_id)
            )
        );
    }
    return $order_ids;
}