$sql = "JOIN (
				SELECT post_parent AS post_id,meta_key,meta_value
				FROM $wpdb->postmeta
				JOIN $wpdb->posts
					ON $wpdb->posts.ID = $wpdb->postmeta.post_id
				WHERE meta_key = 'winning_bid_value'
				UNION ALL
				SELECT post_id,meta_key,meta_value
				FROM $wpdb->postmeta
				JOIN $wpdb->posts
					ON $wpdb->posts.ID = $wpdb->postmeta.post_id
				WHERE meta_key ='start_price'
				AND post_id NOT IN (
					SELECT post_parent
					FROM $wpdb->posts
					WHERE post_status = 'winning')
			) AS new_meta
				ON $wpdb->posts.ID = post_id AND (meta_key = 'start_price' OR meta_key = 'winning_bid_value')";