我需要回显折扣在20%-40%之间的产品。我尝试使用元查询，但它并没有比较愤怒的百分比。我的代码：

<ul class="products">
    <?php

        $args = array(
            \'post_type\'      => \'product\',
            \'posts_per_page\' => 4,
            \'meta_query\'     => array(
                    \'relation\' => \'BETWEEN\',
                    array( // Simple products type
                        \'key\'           => \'_sale_price\',
                        \'value\'         => 0,
                        \'compare\'       => \'>\',
                        \'type\'          => \'numeric\'
                    ),
                    array( // Simple products type
                        \'key\'           => \'_sale_price\',
                        \'value\'         => 1000,
                        \'compare\'       => \'<\',
                        \'type\'          => \'numeric\'
                    )
                )
        );
        $loop = new WP_Query( $args );
        if ( $loop->have_posts() ) {
            while ( $loop->have_posts() ) : $loop->the_post();
                woocommerce_get_template_part( \'content\', \'product\' );
            endwhile;
        } else {
            echo __( \'No products found\' );
        }
        wp_reset_postdata();
    ?>
</ul>

global $product; 
$percentage = round( ( ( $product->regular_price - $product->sale_price ) / $product->regular_price ) * 100 );