SQL SUM operation of multiple subqueries

Question

i have the following mysql database table designed,

ticket(id, code, cust_name);
passenger(id, ticket_id, name, age, gender, fare);
service(id, passenger_id,         


        

Answer 1

What about this?

SELECT 
    SUM(fare) as total_fare,
    SUM(cost) as total_cost as total_service_cost
FROM
    ticket
JOIN passenger ON passenger.ticket_id = ticket.id
JOIN service ON passenger.id = service.passenger_id

If you need to sum for each ticket then add GROUP BY ticket.id