Re: [SQL] Finding the "most recent" rows

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От Julian Scarfe
Тема Re: [SQL] Finding the "most recent" rows
Дата
Msg-id 37204BB5.B6CD57B9@scigen.co.uk
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Ответ на Re: [SQL] Finding the "most recent" rows  (Tom Lane <tgl@sss.pgh.pa.us>)
Ответы Re: [SQL] Finding the "most recent" rows
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Tom Lane wrote:
> 
> SELECT DISTINCT ON place * FROM table ORDER BY place, time DESC;
> 
> might do the right thing.  It *seems* to select the first row for each
> value of place.  I've never seen a spec for this feature, however, so
> I'm not sure if it's reliable or not...

Works a treat when I try it on the "real" database (using 6.4.2). It seems
very efficient. I didn't realise that "DISTINCT ON" worked that way with an
"ORDER BY".

I must say I'm overwhelmed by the variety of constructive responses to my
request.  Thank you all very much.  It beats the hell out of sitting as no 17
in a premium rate telephone queue for support from a vendor of a "commercial"
product.
-- 

Julian Scarfe


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