Sql derby Java Database

String query= "select count(*) from (select distinct FlightId, DayId from Bookings))";

Count = connection.prepareStatement(query);

What Is the correct prepare Statement syntax to count the unique combinations of FlightId and DayID colums.

For instance counting how many times (0,0) appears

(0,1)

(0,2)

(1,0)

etc

Table name Bookings

10 11 12 BOOKINGID CUSTOMERID FLIGHTID DAYID 1 2 1 3 7 0 0 1 9 0 0 1 10 2 2 4 13 14