JPA @repository @Query Can handle a null entity?

Question

I am doing a project with jpa and spring , and i need to do a query like this:

Select models.dto.dealCalendarDTO(d, c) from deal d left outer join calendar c on calendar.deal_id=deal.id;

Or

Select d,c from deal d left outer join calendar c on calendar.deal_id=deal.id;

When I try the first one I have this error: java.lang.NullPointerException: null

When I use the second one, I have this one

Caused by: java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.IdentNode 
 \-[IDENT] IdentNode: 'c' {originalText=c}

I did it with classic SQL without a problem, but I think I am missing something.

Answer 1

The NullPointerException in the first query because you are doing a left join and this maybe cause that c Calendar will be null and you are trying to access it in the DTO function