Re: Selecting latest value

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От Patrik Kudo
Тема Re: Selecting latest value
Дата
Msg-id Pine.BSF.4.31.0109201555480.17720-100000@tb303.partitur.se
обсуждение исходный текст
Ответ на Re: Selecting latest value  (Haller Christoph <ch@rodos.fzk.de>)
Ответы Re: Selecting latest value II  (Haller Christoph <ch@rodos.fzk.de>)
Re: Selecting latest value  (Stephan Szabo <sszabo@megazone23.bigpanda.com>)
Re: Selecting latest value  (Tom Lane <tgl@sss.pgh.pa.us>)
Список pgsql-sql
On Thu, 20 Sep 2001, Haller Christoph wrote:

> Try
> create NEWtable (userid text, val integer, ts timestamp);
> insert into NEWtable
> select userid, val, max(ts) from table group by userid, val;

That won't work. That will give me multiple userid-val combinations. Sure,
the userid-val combinations will be unique, but I want unique userids
with only the latest val for each userid.

/Patrik Kudo

> >
> > Hi,
> >
> > I have a table which basically looks like this:
> >
> > create table (userid text, val integer, ts timestamp);
> >
> > This table holds multiple values for users, timestamped for history
> > reasons.
> >
> > Now I need to fetch the latest val for each userid to insert into a new
> > table (with about the same schema, except for uniqueness on userid).
> > I belive this should be a trivial task, but I'm experience total lack of
> > insight here...
> >
> > Comments?
> >
> > /Patrik Kudo
> >
>



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