SELECT EXTRACT(dow FROM sellout_date),SUM(sellout)*7 /
(
  SELECT SUM(sellout)
  FROM client_008.sales_places_cost_updated
  WHERE sellout_date BETWEEN '2017-04-30'::TIMESTAMP - '27 days'::INTERVAL AND '2017-04-30'::TIMESTAMP
) AS vta_dow
FROM client_008.sales_places_cost_updated
WHERE sellout_date BETWEEN '2017-04-30'::TIMESTAMP - '6 days'::INTERVAL AND '2017-04-30'::TIMESTAMP
GROUP BY 1