SELECT min(value) AS min, max(value) AS max FROM `prices` WHERE exists(SELECT * FROM `variants` WHERE `prices`.`variant_id` = `variants`.`id` AND `pack_quantity` = (SELECT max(pack_quantity) FROM `variants` AS `v2` WHERE product_id = `variants`.product_id AND `available_quantity` > '0')) AND `currency` = 'RUB' LIMIT 1