Re: Aggregates containing outer references don't work per

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От Jan Wieck
Тема Re: Aggregates containing outer references don't work per
Дата
Msg-id 3EDF768B.5060607@Yahoo.com
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Ответ на Re: Aggregates containing outer references don't work per spec  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
>> When we considered outervar1 as a constant, we could do the aggregate in
>> the subquery using computations, but when SUM(outervar1) is computed in
>> an above query, combining that with anything that is part of different
>> query level makes no sense to me because those variables might not even
>> exist at the level that aggregate is being computed.
> 
> Sure they will.  They can only be outer (up-level) references, else the
> parser would not have resolved them in the first place.
> 
> If you accept that SUM(localvar + outervar) is a sensible computation,
> then I think you must accept that SUM(outervar1 + outervar2) makes sense
> too.  It's actually the exact same computation, it's just being
> referenced from within a sub-query.

What is SUM(up1levelvar + up2levelsvar) considered to be? Would that be 
the same as SUM(localvar + outervar) one level up?


Jan

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