hibernate sql query with distinct and order by - sql

Question

I have this query:
"select distinct d from Dance d " +
"inner join d.meisterschaftDances ms " +
"inner join ms.danceRegistrations dr " +
"inner join dr.user u " +
"where (u.id = :userId " +
"or d.user.id = :userId) " +
"AND ms.meisterschaft.open = FALSE " +
"order by ms.meisterschaft.organizer.id, " +
"d.discipline, d.age, d.category, " +
"d.class"
The logic would be perfect for me but as we know distinct is not so easy with order by.
I get the same dance several times because the inner join to meisterschaftDances can have several references.
Sadly I dont know how to rewrite my query in such a way that it is working. Can somebody show me an example which would work. Thanks

Answer 1

As it's stated in the hibernate documentation:
For JPQL and HQL, DISTINCT has two meanings:
It can be passed to the database so that duplicates are removed from a result set
It can be used to filter out the same parent entity references when join fetching a child collection
You are interested in the second case, so, you need to add the QueryHints.HINT_PASS_DISTINCT_THROUGH hint, like below:
List<Dance> dances = entityManager.createQuery(
"select distinct d " +
"from Dance d " +
"inner join d.meisterschaftDances ms ...", Dance.class)
.setHint( QueryHints.HINT_PASS_DISTINCT_THROUGH, false )
.getResultList();
P.S. But the above approach may be not workable in some hibernate versions due to bugs (See for example HHH-13517 and HHH-13280)