if ( have_posts() ) :

$args = array(
‘post_type’ => ‘product’,
‘meta_query’ => array(
‘relation’ => ‘OR’,
array( // Simple products type
‘key’ => ‘_sale_price’,
‘value’ => 0,
‘compare’ => ‘>’,
‘type’ => ‘numeric’
),
array( // Variable products type
‘key’ => ‘_min_variation_sale_price’,
‘value’ => 0,
‘compare’ => ‘>’,
‘type’ => ‘numeric’
)
)
);

query_posts( $args );