SELECT
    T.week_number,
    T.ticket_amount,
    T.festival_week,
    T.festival_name
FROM
(
(SELECT
        EXTRACT (week FROM flights.departure_time) AS week_number,
        COUNT(ticket_flights.ticket_no) AS ticket_amount
    FROM
        airports
    INNER JOIN
        flights
    ON
        airports.airport_code = flights.arrival_airport
    INNER JOIN
        ticket_flights
    ON
        flights.flight_id = ticket_flights.flight_id
    WHERE
        airports.city = 'Москва'
        AND CAST(flights.departure_time AS date) BETWEEN '2018-07-23' AND '2018-09-30'
    GROUP BY
        week_number
) t
LEFT JOIN
(SELECT
        festival_name,
        EXTRACT (week FROM festivals.festival_date) AS festival_week
    FROM
        festivals
    WHERE
        festival_city = 'Москва'
      AND CAST(festivals.festival_date AS date) BETWEEN '2018-07-23' AND '2018-09-30'
) t2
ON
    t.week_number = t2.festival_week
) AS T