Cannot create TypedQuery for query with more than one return using requested result type, despite ha-CodePudding

I have gone through other similar questions on this topic and found that my setup is correct(at least confirms to what others had suggested in the past). I do have a dedicated AllRecordsDTO for the purpose of this query and it does have all the necessary fields for successful mapping of the query result.

AllRecordsDTO.java :

@NoArgsConstructor
@AllArgsConstructor
@ToString
public class AllRecordsDTO {

    @Getter
    @Setter
    private String recordName;

    @Getter
    @Setter
    private String recordTypeName;

    @Getter
    @Setter
    private String statusName;

    @Getter
    @Setter
    private String createdByUserId;

    @Getter
    @Setter
    private String createdDateTime;

    @Getter
    @Setter
    private String lastChangedByUserId;

    @Getter
    @Setter
    private String lastChangedDateTime;

}

The allRecordsQuery query

    select r.recordName,
       rt.recordTypeName,
       s.name,
       usi.userId,
       r.createdDateTime,
       usi1.userId,
       r.lastChangedDateTime
from Record r
         left join Section s on s.id = r.statusId
         left join UniqueSecurityIdentifier usi on usi.id = r.createdByUserId
         left join RecordType rt on rt.id = r.recordTypeId
         left join UniqueSecurityIdentifier usi1 on usi1.id = r.lastChangedByUserId

The line that throws the exception :

Query<AllRecordsDTO> createdQuery = statelessSession.createQuery(allRecordsQuery, AllRecordssDTO.class);

All the Entity fields used in the query above are String(even the date fields are String in the above entities).

I am not sure what could have gone wrong.

CodePudding user response：

What you are trying is not possible with JPA.

You habe to use the Constructor Expression.

select NEW <packagename>.AllRecordsDTO(r.recordName,
       rt.recordTypeName,
       s.name,
       usi.userId,
       r.createdDateTime,
       usi1.userId,
       r.lastChangedDateTime)
from Record r
         left join Section s on s.id = r.statusId
         left join UniqueSecurityIdentifier usi on usi.id = r.createdByUserId
         left join RecordType rt on rt.id = r.recordTypeId
         left join UniqueSecurityIdentifier usi1 on usi1.id = r.lastChangedByUserId

Please also checkout the Hibernate documentation: https://docs.jboss.org/hibernate/orm/current/userguide/html_single/Hibernate_User_Guide.html#hql-select-clause