I have an entity that has two nullable attributes: a team and a person. Both of them are entities themself and one of them is always null.
Now I'd like to order the entity by the team's and the peron's name combined in one column. But because one of them is null, simply using "order by team.name, person.name" doesn't work.
How can I do that?

You can create a special, read-only property on the main entity to be sorted, which internally checks for nulls and always returns a composite name or "".

At the HQL level, you can experiment with the coalesce() expression, which returns the first non-null parameter of a parameter list.