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From Pawel Veselov <>
Subject Re: left joins, wheres and IN
Date Wed, 28 Dec 2011 17:40:19 GMT

On Wed, Dec 28, 2011 at 7:57 AM, Pinaki Poddar <> wrote:

> How about
> select a from Alpha a
>            where {predicates on a}
>            and not exists (select b from Beta b where b.alpha = a and
> {other predicates on b})
That would of course give the results, but it's a nested loop, and over a
sub-query too. I don't believe OpenJPA (or any other JPA) would convert
that to a left join (though it should technically be possible to do so) in
any dialect.

My original concern was about true left joins.

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