如何使用扩展对象中的字段使用左联接创建hql查询

Question

I have this class called Locatable:

 @Entity
 @Table(name = "locatable")
 @PrimaryKeyJoinColumn(name = "device_id", referencedColumnName = "id")
 open class Locatable: Device() {

 @Basic
 @Column(name = NAME_COLUMN)
 var name: String? = null
    }

as you can see Locatable extended Device, Device looks like this:

@Entity
@Table(name = "device")
@Inheritance(strategy = InheritanceType.JOINED)
abstract class Device {

 @Id
 @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGen")
@SequenceGenerator(name = "sequenceGen", sequenceName = "devices_id_seq", allocationSize = 1)
@Column(name = ID_COLUMN)
open var id: Long = 0

@Basic
@Column(name = GROUP_COLUMN)
open var groupId: Long = 0
}

Now, Im trying to make a repo using hql like this:

interface LocatableRepo : JpaRepository<Locatable, Long> {

  @Query("SELECT l FROM Locatable l LEFT JOIN FETCH l.Device WHERE l.groupId IN ?1")
fun getByGroupIdIn(ids: List<Long>): List<Locatable>
}

but from some reason it's not working for me... probably i do it wrong, Thank you

Answer 1

groupdId is of entity Device so it should be

LEFT JOIN FETCH l.Device d WHERE d.groupId 

you give a name to the device join and use that when referencing column belonging to device