现在我的查询返回航班地图及其机票计数。
我的目标是从查询结果(count(t) < f.aircraft.model.passengersSeatsQuantity)
中排除完整的航班。但我无法设法创建这样的查询。因此,现在我必须在方法中排除完整的航班,这令人沮丧,因为我认为应该有办法在查询中进行。任何人都可以帮助构建查询?附:我现在可以使用Criteria API
String queryString = "SELECT f, COUNT(t)"
+ " FROM Flight f"
+ " JOIN FETCH f.tickets AS t"
+ " WHERE f.departureAirport=:departureAirport"
+ " GROUP BY t.flight"
+ " ORDER BY f.id ASC";
Query query = em.createQuery(queryString);
query.setParameter("departureAirport", departureAirport);
Map<Flight, Long>) flightsTicketCountMap =
query.getResultList().stream()
.collect(Collectors.toMap(resultElement -> (Flight) (((Object[]) resultElement)[0]),
resultElement -> (Long) (((Object[]) resultElement)[1])));
//below i exclude full flights from map, but i want to do it in query
Map<Flight, Long> availableFlightTicketPriceMap = new HashMap();
for (Map.Entry<Flight, Long> entry : flightsTicketCountMap.entrySet()) {
flight = entry.getKey();
ticketsQuantity = entry.getValue();
if (flight.getAircraft().getModel().getPassengersSeatsQuantity() > ticketsQuantity) {
availableFlightTicketPriceMap.put(flight, calculateTicketPrice(tariffsDetails, flight, ticketsQuantity));
}
}
更新。
飞机和型号都有急切的政策,但HAVING COUNT(t) < f.aircraft.model.passengersSeatsQuantity
热点异常com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown column aircraftmo3_.passenger_seats_quantity in having clause
public class Flight{
@OneToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "aircraft_id")
private Aircraft aircraft;
}
public class Aircraft{
@ManyToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "model_id")
private AircraftModel model;
}
public class AircraftModel{
@Column(name = "passenger_seats_quantity")
@Range(min = 0, max = 450)
private Integer passengersSeatsQuantity;
}
答案 0 :(得分:1)
您是否尝试过添加HAVING
条款?
SELECT f, COUNT(t)
FROM Flight f
JOIN FETCH f.tickets AS t
WHERE f.departureAirport=:departureAirport
GROUP BY t.flight
HAVING COUNT(t) < f.aircraft.model.passengersSeatsQuantity
ORDER BY f.id ASC