[Spring] QueryDsl 에러 query specified join fetching, but the owner of the fetched association was not present in the select list

오류 설명

QueryDsl에서 다음과 같이 fetchJoin()을 사용하여 코드를 작성하였더니 다음과 같은 에러가 발생했다.

코드

public List<A> findOne( {
        return queryFactory
                .selectFrom(QA.a)
                .join(QA.a.b, QB.b).fetchJoin()
                .join(QA.a.b.c, QC.c).fetchJoin()
                .fetch();
    }

에러

query specified join fetching, but the owner of the fetched association was not present in the select list

오류 해결

public List<A> findOne( {
        return queryFactory
                .selectFrom(QA.a)
                .join(QA.a.b, QB.b).fetchJoin()
                .join(QB.b.c, QC.c).fetchJoin()
                .fetch();
    }

참고
https://www.inflearn.com/questions/240949/fetchjoin-%EC%97%90%EB%9F%AC-%EB%B0%9C%EC%83%9D