SELECT
    SBQ.week_number,
    SBQ.ticket_amount,
    SBQ1.festival_week,
    SBQ1.festival_name
FROM
    (SELECT
        EXTRACT(WEEK FROM arrival_time) AS week_number,
        COUNT(ticket_flights.ticket_no) AS ticket_amount
     FROM
         flights
     INNER JOIN ticket_flights ON ticket_flights.flight_id = flights.flight_id
     WHERE
         arrival_time BETWEEN '2018-07-23' AND '2018-09-30' AND arrival_airport IN ('VKO', 'SVO', 'DME', 'ZIA')
     GROUP BY
         week_number
     ) AS SBQ
LEFT JOIN
(SELECT
    EXTRACT(WEEK FROM festival_date) AS festival_week,
    festival_name
 FROM
     festivals
 WHERE
    festival_date BETWEEN '2018-07-23' AND '2018-09-30' AND festival_city = 'Москва'
) AS SBQ1
ON
    SBQ.week_number = SBQ1.festival_week;