I've following classes with FK relation:
Q (1:n) S
Q (1:n) A ( n:1 ) S The relation Q-A is optional (and A-S as well).
Think about Questions with predefined Select options (as answers) and a large number of given Answers.

Now I want to have all Q,S,A with Q,S,null when there is no Q-A relation.
In native SQL this is rather straight forward (fragment):

But how to express this in HQL? I got this far:
with Q.setS the OneToMany mapping of Q to S.
But how to bring in the relation between A and S? (I know that in this case a solution via Q-in-S-oj-A exists, but this is a simplification of a complexer problem I have).

An other slightly different pattern is that the relation between A (n:1) S is not a FK relation but an expression. How to take care of that in HQL?

Thanks,
Erik

The equivalent to the keyword "on" in HQL is "with"!
But there are many restrictions :

http://opensource.atlassian.com/project ... e/HHH-1673

Thanks for the answer and the link to the issue. This is my first hibernate project with some serious queries and I'm forced to go to native SQL. I might get around with a patched version, but I'm not that trained to get it done is reasonable time. Have people posted hibernate distribution with including this fix?

Thanks,

Erik

I'm actually working on a patch for this point that will remove some of the restrictions (but not all of them!)
I will post it once it's done.