SELECT `psp`.`product_id`, `sp`.`product_id`
  FROM `discount_coupons_lot_showcases` AS `dcls`
 INNER
  JOIN `showcases` AS `s`
    ON s.id = dcls.showcase_id
  LEFT
  JOIN `product_selector` AS `ps`
    ON ps.id = s.product_selector_id
  LEFT
  JOIN `product_selector_products` AS `psp`
    ON ps.id = psp.product_selector_id
  LEFT
  JOIN `showcases_products` AS `sp`
    ON `sp`.`showcase_id` = `s`.`id`
 WHERE (`dcls`.`discount_coupons_lot_id` = 9)
   AND (
       `sp`.`product_id` IN (11)
        OR `psp`.`product_id` IN (11)
       )
   AND (NOT(`s`.`c_removed`))