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Task 111: 
Get statistics on flights departing from Domodedovo Airport (DME) in August 2017.
Output the result as a table with columns:
     count_departed - the total number of flights departing from the airport,
     count_delayed - the number of delayed flights (a flight that actually took off more than half an hour later than scheduled is considered delayed) and
     delayed_flights_rate - percentage of delayed flights rounded to two decimal places.

Use PostgreSQL syntax to write your answer. Descriptions of tables are provided in the right pane.

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Bookings Database (PostgreSQL)

The subject area of this database is airline flights through various airports.

ER diagram of the Bookings database

The Bookings Database contains 8 tables:

aircrafts_data - table of aircrafts.
  • aircraft_codeUnique code for each aircraft.
  • modelAircraft model name in English and Russian in JSON format.
  • rangeAircraft fly range in kilometers.
  • PRIMARY KEY, btree (aircraft_code)
aircraft_codemodelrange
1773{"en": "Boeing 777-300", "ru": "Боинг 777-300"}11100
airports_data - table of airports.
  • airport_codeUnique code for each airport.
  • airport_nameAirport name in English and Russian in JSON format.
  • cityAirport city in English and Russian in JSON format.
  • coordinatesAirport coordinates as POINT(longitude, latitude).
  • timezoneAirport timezone name.
  • PRIMARY KEY, btree (airport_code)
airport_codeairport_namecitycoordinatestimezone
1YKS{"en": "Yakutsk Airport", "ru": "Якутск"}{"en": "Yakutsk", "ru": "Якутск"}(129.77099609375,62.0932998657227)Asia/Yakutsk
boarding_passes - table of boarding passes.
  • ticket_noTicket number.
  • flight_idFlight identificator.
  • boarding_noBoarding pass number.
  • seat_noSeat number.
  • PRIMARY KEY, btree (ticket_no, flight_id)
  • UNIQUE CONSTRAINT, btree (flight_id, boarding_no)
  • UNIQUE CONSTRAINT, btree (flight_id, seat_no)
  • FOREIGN KEY (ticket_no, flight_id) REFERENCES ticket_flights(ticket_no, flight_id)
ticket_noflight_idboarding_noseat_no
100054352123513062512D
bookings - table of bookings.
  • book_refBooking number.
  • book_dateBooking date.
  • total_amountTotal booking cost.
  • PRIMARY KEY, btree (book_ref)
book_refbook_datetotal_amount
100000F2017-07-05 00:12:00+00265700.00
flights - table of flights.
  • flight_idFlight ID.
  • flight_noFlight number.
  • scheduled_departureScheduled departure time.
  • scheduled_arrivalScheduled arrival time.
  • departure_airportAirport of departure.
  • arrival_airportAirport of arrival.
  • statusFlight status.
  • aircraft_codeAircraft code, IATA.
  • actual_departureActual departure time.
  • actual_arrivalActual arrival time.
  • PRIMARY KEY, btree (flight_id)
  • UNIQUE CONSTRAINT, btree (flight_no, scheduled_departure)
flight_id flight_no scheduled_departure scheduled_arrival departure_airport arrival_airport status aircraft_code actual_departure actual_arrival
11185PG01342017-09-10 06:50:00+002017-09-10 11:55:00+00DMEBTKScheduled319
seats - table of aircraft seats.
  • aircraft_codeAircraft code, IATA.
  • seat_noSeat number.
  • fare_conditionsTravel class.
  • PRIMARY KEY, btree (aircraft_code, seat_no)
  • FOREIGN KEY (aircraft_code) REFERENCES aircrafts(aircraft_code) ON DELETE CASCADE
aircraft_codeseat_nofare_conditions
13192ABusiness
ticket_flights - ticket to flights relations.
  • ticket_noTicket number.
  • flight_idFlight ID.
  • fare_conditionsTravel class.
  • amountTravel cost.
  • PRIMARY KEY, btree (ticket_no, flight_id)
  • FOREIGN KEY (flight_id) REFERENCES flights(flight_id)
  • FOREIGN KEY (ticket_no) REFERENCES tickets(ticket_no)
ticket_no flight_id fare_conditions amount
1000543215977630625Business42100.00
tickets - table of tickets.
  • ticket_noTicket number.
  • book_refBooking number.
  • passenger_idPassenger ID.
  • passenger_namePassenger name.
  • contact_dataPassenger contact information.
ticket_no book_ref passenger_id passenger_name contact_data
1000543200098706B0468149 604011VALERIY TIKHONOV{"phone": "+70127117011"}
  • PRIMARY KEY, btree (ticket_no)
  • FOREIGN KEY (book_ref) REFERENCES bookings(book_ref)