| From: | Andreas Kretschmer <andreas(at)a-kretschmer(dot)de> |
|---|---|
| To: | Matthias Nagel <matthias(dot)h(dot)nagel(at)gmail(dot)com>, pgsql-sql(at)postgresql(dot)org |
| Subject: | Re: Reuse temporary calculation results in an SQL update query |
| Date: | 2012-09-29 10:56:35 |
| Message-ID: | 1237868969.148407.1348916195838.JavaMail.open-xchange@ox.ims-firmen.de |
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| Lists: | pgsql-sql |
Matthias Nagel <matthias(dot)h(dot)nagel(at)gmail(dot)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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