Question

我正在选择两个id列但指定了错误：

org.hibernate.QueryException: **query specified join fetching, but the owner of the fetched association was not present in the select list** 

[FromElement{explicit,not a collection join,fetch join,fetch non-lazy properties,classAlias=r,role=null,tableName=REVISIONS,tableAlias=revision1_,origin=ENTITY_CHANGED_IN_REVISION entitychan0_,columns={entitychan0_.REV_ID ,className=ru.csbi.registry.domain.envers.Revision}}] [ select ec.id as entityChangeId, r.id as revisionId from ru.csbi.registry.domain.envers.EntityChange as ec  inner join fetch ec.revision as r  where ec.groupEntityId = :groupEntityId and ec.groupName = :groupName  and r.timestamp < :entityDateFrom  and r.timestamp > :entityDateTo  and (        ec.revisionType in (0, 5, 1, 4, 2 )       and not ( ec.otherGroupEntityModified = false and ec.thisGroupEntityModified = true and ec.rowDataModified = false and ec.collectionOfNotGroupEntityModified = false   )      )  group by ec.id, r.id  having count(*) > :start order by r.id desc]

一些代码：

String hql = " select ec.id as entityChangeId, r.id as revisionId from EntityChange as ec " +
            " inner join fetch ec.revision as r " +
            " where ec.groupEntityId = :groupEntityId" +
            " and ec.groupName = :groupName " +
            " and r.timestamp < :entityDateFrom " +
            " and r.timestamp > :entityDateTo " +
            " and ( " +
            "       ec.revisionType in (" + 
                        RevisionType.ADD.getRepresentation() + ", " + 
                        RevisionType.ONLY_DATA_PROPERTY_MOD.getRepresentation() + ", " +
                        RevisionType.BOTH_COLLECTION_AND_PROPERTY_MOD.getRepresentation() + ", " +
                        RevisionType.ONLY_COLLECTION_PROPERTY_MOD.getRepresentation() + ", " +
                        RevisionType.DEL.getRepresentation() +
                    " ) " +
            "     and not ( "+
                    "ec.otherGroupEntityModified = false and " +
                    "ec.thisGroupEntityModified = true and " +
                    "ec.rowDataModified = false and " +
                    "ec.collectionOfNotGroupEntityModified = false " +
                "  ) " +
            "     ) " +
            " group by ec.id, r.id " +
            " having count(*) > :start" +
            " order by r.id desc";

如何解决错误以及我做错了什么？

Answer 1

使用常规join代替join fetch（顺便说一句，默认情况下为inner）：

String hql = " select ec.id as entityChangeId, r.id as revisionId from EntityChange as ec " + 
        " join ec.revision as r " + ...

正如错误消息所示，join fetch在这里没有意义，因为它是一个性能提示，迫使急切加载集合。

Answer 2

由于您需要联接提取，因此删除提取将无法满足您的需求。

您应该改为指定一个计数查询。

假设您要对结果进行分页，下面是jpa查询，它将id作为参数，并且会导致您指定的问题，第二个查询通过向其添加计数查询来解决此问题。

注意：fk_field是tableA中具有一对多rln的属性。计数查询不使用联接获取。

@Query(value = "from TableA a LEFT JOIN FETCH a.fk_field where a.id = :id") 

@Query(value = "from TableA a LEFT JOIN FETCH a.fk_field where a.id = :id", 
  countQuery = " select  count(a) from TableA a left join a.fk_field where a.id = :id")

Answer 3

您必须将您的相关项目列放入选择子句中

select ec.id as entityChangeId, r.id as revisionId, **r.revision** from EntityChange as ec " +
        " inner join fetch ec.revision as r " +

查询指定的连接提取，但提取的关联的所有者不在选择列表中

3 个答案: