Query 1

// WP_Query arguments
$args = array(
	'post_type'              => array( 'product' ),
	'post_status'            => array( 'publish' ),
	'nopaging'               => true,
	'paged'                  => '1',
	'posts_per_page'         => '20',
	'orderby'                => 'rand',
	'tax_query'              => array(
		'relation' => 'AND',
		array(
			'taxonomy'         => 'product_cat',
			'field'            => 'term_id',
			'operator'         => 'IN',
			'include_children' => false,
		),
	),
	'cache_results'          => false,
	'update_post_meta_cache' => false,
	'update_post_term_cache' => false,
);

// The Query
$query = new WP_Query( $args );

// The Loop
if ( $query->have_posts() ) {
	while ( $query->have_posts() ) {
		$query->the_post();
		// do something
	}
} else {
	// no posts found
}

// Restore original Post Data
wp_reset_postdata();