Schema flight (flightNumber, airlinecode, date price, seating, IATA, IATALands, time, timeland) customer (name, phone, agentName) agent (name, fee, phone) airport (IATA, city, type) booking ( name, flightNumber, airlinecode, date seat) Customer Phone name agentName seat price Aline Sean John Booking name flight airline Date Nber ode Tom AA 207 3.4.21 Bill UA 146 3.4.21 Sarah MEA 205 3.4.21 Airport IATA City ORD Chicago MDW Boston BOS Boston A1 140 A3 345 4 560 agent Name Aline Sean John 8899452552 Tom 7814449884 Bill 7753698887 Sarah Agent agentName Price Aline 150 Sean 460 John 150 Flight flightNumber airlinecode 207 UA 146 MEA 205 phone 7785667860 7834438765 9873434444 Type International International International Price 200 400 250 Seat 5 11 4 IATA IATALands BOS EWR ERW MCO FRA BEY timeDep. 12:00 14:00 12:00 Time Arr 13:05 18:05 13:05 date 3.4.21 3.4.21 3.4.21 ER diagram below shows a flight management system allows viewing flight information and booking flights. The flight includes the airline code, flight number, price, seating. Each flight takes off and lands in an airport. The airport has IATA (unique code), city, and type. A customer has a name and a phone. An agent takes care of customers. Each agent has a name and a booking fee. Airport takeoff flight airline Code flightNumber time Price Seating City Type time seat land booking time Customer Name phone Agent Name fee Takecare Write a SQL expression that returns the average price of items bought by each customer from each agent