Buscar pedidos por SKU

/* Permitir buscar pedidos por SKU */
add_filter( 'woocommerce_shop_order_search_results', 'ayudawp_buscar_pedidos_por_sku', 9999, 3 );
function ayudawp_buscar_pedidos_por_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; 
}