From: | "Joel Burton" <jburton(at)scw(dot)org> |
---|---|
To: | "Chuck Kimber" <chuckk(at)ext(dot)usu(dot)edu> |
Cc: | Pgsql-novice(at)postgresql(dot)org |
Subject: | RE: running totals |
Date: | 2000-12-06 22:44:30 |
Message-ID: | 3A2E7AFE.1129.702A05B@localhost |
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Thread: | |
Lists: | pgsql-novice |
> >CREATE VIEW tape_view AS
> >SELECT id, tape_name, sum(runtime)
> >FROM tape t,
> >show s
> >WHERE t.id = s.tape_id
> >GROUP BY id, tape_name;
> >
> >Which means you can just
>
> >SELECT * FROM tape_view;
>
> Wow! This is a great idea... I had never thought of using a view
for
> this type of calculation. I always did it the hard way. Question
> though, does the VIEW keep the sum current at all times, or does
it
> just update when a query is run on the VIEW?
The view *IS* a query, really. When you SELECT from the VIEW,
you're really running a SELECT. So, no, merely updating in the the
table doesn't affect the view, only when you select from the view.
--
Joel Burton, Director of Information Systems -*- jburton(at)scw(dot)org
Support Center of Washington (www.scw.org)
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