Plugins activated & WordPress version
WooCommerce 6.0.0-rc.1
WooCommerce Beta Tester 2.0.4
WordPress 5.8.2

Issue description
I get a database error when adding the On Sale Products block in a page.

[WordPress database error You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ') AND meta_key LIKE 'attribute\\_%'' at line 1 for query SELECT post_id as variation_id, meta_key as attribute_key, meta_value as attribute_value FROM wp_postmeta WHERE post_id IN () AND meta_key LIKE 'attribute\\_%' made by require('wp-blog-header.php'), wp, WP->main, WP->parse_request, do_action_ref_array('parse_request'), WP_Hook->do_action, WP_Hook->apply_filters, rest_api_loaded, WP_REST_Server->serve_request, WP_REST_Server->dispatch, WP_REST_Server->respond_to_request, WP_REST_Block_Renderer_Controller->get_item, render_block, WP_Block->render, Automattic\WooCommerce\Blocks\BlockTypes\AbstractBlock->render_callback, Automattic\WooCommerce\Blocks\BlockTypes\AbstractProductGrid->render, Automattic\WooCommerce\Blocks\BlockTypes\AbstractProductGrid->get_products, Automattic\WooCommerce\Blocks\BlockTypes\AbstractProductGrid->prime_product_variations

Steps to reproduce
Go to Pages > Add New > then add the "On sale Products" block. This action triggers the database error mentioned above.