如何使用 LEFT JOIN 创建 JPA NamedQuery

Question

I have two entities: Car and Reservation. I would like to create named query with LEFT JOIN. I was trying to do this like it is described here How to create JPA query with LEFT OUTER JOIN but it doesn't work. Do you have any idea what is wrong in my query? I would like to show Cars which have NULL reservations. Anyway even with JOIN it does not work. After starting application I have an error:

Caused by: org.hibernate.HibernateException: Errors in named queries: Car.findAll
    at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:495) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:444) ~[hibernate-core-5.0.12.Final.jar:5.0.12.Final]
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:879) ~[hibernate-entitymanager-5.0.12.Final.jar:5.0.12.Final]
    ... 22 common frames omitted

In principle I would like to achieve this query which in MySQL works

SELECT distinct * FROM car c LEFT JOIN reservation r ON c.id = r.car_id WHERE c.producer='producer' AND c.model='model' AND c.type='type' 
AND (r.date_of_rent < 'date1' AND r.date_of_return < 'date1') OR (r.date_of_rent > 'date2') OR r.date_of_rent IS NULL;

Car Entity

import java.io.Serializable;
import java.util.List;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;

@Entity
@NamedQuery(name = "Car.findAll", query = "SELECT c FROM Car c LEFT JOIN c.reservation r WHERE c.producer=:producer "
        + "AND c.type=:type AND c.dailyPrice=:dailyPrice")
public class Car implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String producer;
    private String model;
    private int seatsNumber;
    private String type;
    private String registrationNumber;
    private double dailyPrice;
    private String description;
    @OneToMany(mappedBy = "car")
    private List<Reservation> reservations;

Reservation Entity

import java.io.Serializable;
import java.sql.Date;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;

@Entity
public class Reservation implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @ManyToOne
    private User user;
    @ManyToOne
    private Car car;
    private Date dateOfRent;
    private Date dateOfReturn;

Many thanks for help.

UPDATE

Problem solved. Query should look like this one

import java.io.Serializable;
import java.util.List;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQuery;
import javax.persistence.OneToMany;

@Entity
@NamedQuery(name = "Car.findAll", query = "SELECT DISTINCT c FROM Car c LEFT JOIN c.reservations r WHERE "
        + "c.type=:type AND c.dailyPrice<=:dailyPrice AND ((r.dateOfRent < :dateOfRent AND r.dateOfReturn < :dateOfRent) OR "
        + "(r.dateOfRent > :dateOfReturn) OR (r.dateOfRent IS NULL))")
public class Car implements Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String producer;
    private String model;
    private Integer seatsNumber;
    private String type;
    private String registrationNumber;
    private Double dailyPrice;
    private String description;
    @OneToMany(mappedBy = "car")
    private List<Reservation> reservations;

Answer 1

SELECT c FROM Car c LEFT JOIN c.reservation r WHERE c.producer=:producer "
        + "AND c.type=:type AND c.dailyPrice=:dailyPrice

There is an error in this query c.reservation need to be changed to c.reservations .

I would like to show Cars which have NULL reservations.

You can't do it this way. Try to begin from this query:

select c from Car c where not exists (
    select r.id from Reservation r where r.car.id = c.id
)