Re: A fine point about OUTER JOIN semantics

> > In some cases, an outer join with WHERE restrictions reduces to
> > an inner join (so the qualification clauses can be consolidated).
> I recall you having muttered something about that before, but I don't
> see how it works.  Can you give an example of an outer join that
> reduces to an inner join?

Hmm. This example is pretty silly, but afaik it reduces to an inner
join:
 select i, j from t1 left join t2 using (i) where j is not null;

(where t1 has column "i" and t2 has columns "i" and "j").
                    - Thomas