From: Andreas Kretschmer <andreas@a-kretschmer.de>
To: Matthias Nagel <matthias.h.nagel@gmail.com>
To: pgsql-sql@postgresql.org
Subject: Re: Reuse temporary calculation results in an SQL update query
Date: Sat, 29 Sep 2012 12:56:35 +0200 (CEST)
Message-ID: <1237868969.148407.1348916195838.JavaMail.open-xchange@ox.ims-firmen.de> (raw)
In-Reply-To: <43516431.HfO3TYfNBy@hek506>
References: <43516431.HfO3TYfNBy@hek506>
Matthias Nagel <matthias.h.nagel@gmail.com> hat am 29. September 2012 um 12:49
geschrieben:
> Hello,
>
> is there any way how one can store the result of a time-consuming calculation
> if this result is needed more than once in an SQL update query? This solution
> might be PostgreSQL specific and not standard SQL compliant. Here is an
> example of what I want:
>
> UPDATE table1 SET
> StartTime = 'time consuming calculation 1',
> StopTime = 'time consuming calculation 2',
> Duration = 'time consuming calculation 2' - 'time consuming calculation 1'
> WHERE foo;
The Duration - field is superfluous ...
As far as i know there is no way to re-use the result.
Regards, Andreas
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To: pgsql-sql@postgresql.org
Cc: andreas@a-kretschmer.de, matthias.h.nagel@gmail.com
Subject: Re: Reuse temporary calculation results in an SQL update query
In-Reply-To: <1237868969.148407.1348916195838.JavaMail.open-xchange@ox.ims-firmen.de>
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