Diplay taxonomy products in page

Unfortunately, that’s not easy to achieve.

WooCommerce gets the products on sale with an internal function called wc_get_product_ids_on_sale, that offers no filter we can hook in to, to add the products on sale because of taxonomy rules:

function wc_get_product_ids_on_sale() {
	// Load from cache.
	$product_ids_on_sale = get_transient( 'wc_products_onsale' );

	// Valid cache found.
	if ( false !== $product_ids_on_sale ) {
		return $product_ids_on_sale;
	}

	$data_store          = WC_Data_Store::load( 'product' );
	$on_sale_products    = $data_store->get_on_sale_products();
	$product_ids_on_sale = wp_parse_id_list( array_merge( wp_list_pluck( $on_sale_products, 'id' ), array_diff( wp_list_pluck( $on_sale_products, 'parent_id' ), array( 0 ) ) ) );

	set_transient( 'wc_products_onsale', $product_ids_on_sale, DAY_IN_SECONDS * 30 );

	return $product_ids_on_sale;
}

The way we solved that problem in a customer’s website we developed some time ago, was by implementing custom code and a new shortcode that gets the products on sale returned by the wc_get_product_ids_on_sale function, and then we get the taxonomy ones with our internal function wctd_get_product_ids_on_sale, merge them together and create a custom loop to show them all with that new shortcode.

That’s not something we will be able to do for you as this is a free plugin.

We make shortcode and display all sale products on page:

function productsshort() {
global $product;
$product_ids = wctd_get_product_ids_on_sale();
$product_ids2 = implode(",",$product_ids); //converts an array to JSON string
$content = do_shortcode( '[products ids="'.$product_ids2.'" columns="3" orderby="post__in"]' );
return $content;
}
add_shortcode ("productsshort", "productsshort");

I add custom text, when there is no sale products:

function productsshort() {
global $product;
$product_ids = wctd_get_product_ids_on_sale();
$product_ids2 = implode(",",$product_ids); //converts an array to JSON string
if ($product_ids2){
$content = do_shortcode( '[products ids="'.$product_ids2.'" columns="3" orderby="post__in"]' );
} else {
$content = "No products on sale.";
}

return $content;
}
add_shortcode ("productsshort", "productsshort");

Great!