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Problems to use order by a null association [message #610099]

Tue, 21 September 2010 16:56

No real name
Messages: 7
Registered: April 2010

Junior Member

Hello all!

I have two entities, A and B. A has manyToOne association with B. To list all A's ordered by B's in native sql I use this:

select * from A order by fk_idB

* fk_idB is the foreign key

But in jpql I use:

select a from A a order by a.b.idB

But now only the A's that has a B entity are returned. I need to return all A's! How I can do this?

Please someone help me!
Thanks

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Re: Problems to use order by a null association [message #628629 is a reply to message #610099]

Thu, 23 September 2010 09:38

Chris Delahunt
Messages: 862
Registered: July 2009

Senior Member

Hello,

The JPQL "select a from A order by a.b" might work as I believe EclipseLink has optimizations in place to just use the foriegn key. But the spec implies that using a '.' for a relationship should cause an inner join. So to be sure an outer join is used (for instance, if A doesn't have the foreign key), you may want to specify an outer join be used. For example:
"select a from A a outer join a.b b order by b"

Best Regards,
Chris

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