RE: running totals
От | Joel Burton |
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Тема | RE: running totals |
Дата | |
Msg-id | 3A2E7AFE.1129.702A05B@localhost обсуждение исходный текст |
Ответ на | Re: running totals ("Joel Burton" <jburton@scw.org>) |
Ответы |
Re: running totals
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Список | 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@scw.org Support Center of Washington (www.scw.org)
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