From: | Harald Fuchs <hf0722x(at)protecting(dot)net> |
---|---|
To: | pgsql-sql(at)postgresql(dot)org |
Subject: | Re: Question about a select |
Date: | 2005-01-23 15:37:47 |
Message-ID: | puoefg6tro.fsf@srv.protecting.net |
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Lists: | pgsql-sql |
In article <20050122155611(dot)GA6592(at)kaufbach(dot)delug(dot)de>,
Kretschmer Andreas <andreas_kretschmer(at)despammed(dot)com> writes:
> Hi,
> I have a table with this columns: machine, date and area.
> Now i need a view with machine an week, calculated from date, and
> sum(area), where date between CURRENT_DATE and now+N days.
> Okay, this is not the problem, it works fine.
> (the original table and the view is more complex)
> The problem is, i need also rows for machine and week with no entrys in
> the table. For this rows the sum(area) shold be NULL ore 0.
> In other words: for every machine i need M rows, and M must be constant.
Week values don't automagically spring into existance when there are
no corresponding entries in your table. Use a set-returning function
for generating the week values you're interested in, and left-join
your table to the SRF.
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