From: | Manfred Koizar <mkoi-pg(at)aon(dot)at> |
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To: | Alexander Pucher <pucher(at)atlas(dot)gis(dot)univie(dot)ac(dot)at> |
Cc: | pgsql-novice(at)postgresql(dot)org |
Subject: | Re: Sum of two rows |
Date: | 2003-03-10 09:25:27 |
Message-ID: | p9mo6vobt99jslorlel868kgcjqrpe0glc@4ax.com |
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Lists: | pgsql-novice |
On Mon, 10 Mar 2003 11:02:33 +0100, Alexander Pucher
<pucher(at)atlas(dot)gis(dot)univie(dot)ac(dot)at> wrote:
>Let's pretend I want to have a table with 3 columns.
>The first and second should each hold an integer value, the third should
>hold the sum of column1 + column2 as an integer.
>
>The idea behind this table should be that the sum is automatically
>updated, each time I change one of the values in either of the first two
>columns.
Either create your table without the third column and use a view
whenever you need the sum.
Or calculate the sum in a BEFORE INSERT / BEFORE UPDATE trigger.
Servus
Manfred
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