JPQL/HQL 错误：使用 LEFT JOIN 输入结束时出现语法错误答案

【问题标题】：JPQL/HQL ERROR: syntax error at end of input with LEFT JOINJPQL/HQL 错误：使用 LEFT JOIN 输入结束时出现语法错误
【发布时间】：2021-07-11 17:45:51
【问题描述】：

我在尝试执行以下查询时遇到 ERROR: syntax error at end of input：

SELECT appointment FROM Appointment appointment LEFT JOIN DoctorFacilityAppointment dfa

谁能告诉我为什么会出现这个错误？

预约类

public class Appointment implements Serializable {
        
   private static final long serialVersionUID = 1L;
        
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private int id;
        
   @Column(name="start_time")
   private LocalDateTime startTime;
        
   @Column(name="is_valide")
   private boolean isValid;
        
   @ManyToOne
   @JoinColumn(name = "patient_id", referencedColumnName = "id")
   private Patient patient;
    
}

医生设施预约

public class DoctorFacilityAppointment implements Serializable {
        
   private static final long serialVersionUID = 1L;
        
   @Id
   @GeneratedValue(strategy = GenerationType.IDENTITY)
   private int id;
        
   @ManyToOne
   @JoinColumn(name = "appointment_id", referencedColumnName = "id")
   private Appointment appointment;
        
   @ManyToOne
   @JoinColumn(name = "doctor_service_id", referencedColumnName = "id")
   private DoctorFacility doctorFacility;
}

【问题讨论】：

标签： spring-boot hibernate jpa jpql

【解决方案1】：

JPQL/HQL join 应该引用适当实体的关联或组件/嵌入属性。

所以，正确的查询应该是这样的：

select app from DoctorFacilityAppointment dfa left join dfa.appointment app

【讨论】：