Doctrine使用本机查询加入实体

Question

I want join with Left Join an Entity in native Query (ResultSetMappingBuilder) but the fonction addJoinedEntityFromClassMetadata() need relation ...

addJoinedEntityFromClassMetadata( string $class, string $alias, string $parentAlias, object $relation)

But I don't have relation : I want just join table without relation because is not bi-directional relation in entities. Ideally, in return, I want create a field containing the attached entity. :)