Re: dynamic rules?

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: Christopher Dedels <cdedels(at)mygeotivity(dot)com>
Cc: pgsql-sql(at)postgresql(dot)org
Subject: Re: dynamic rules?
Date: 2004-06-04 16:13:40
Message-ID: 20040604161340.GA15526@wolff.to
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On Thu, Jun 03, 2004 at 21:32:47 -0700,
Christopher Dedels <cdedels(at)mygeotivity(dot)com> wrote:
> Is it possible to create a select rule that returns results depending on a
> where clause in the original select statement?
>
> For Example (oversimplified):
>
> CREATE TABLE one (data int);
> CREATE TABLE two (data int);
>
> I make the query:
> SELECT data FROM number WHERE type=1;
>
> If the type is 1 (type=1) I want to return 'SELECT data FROM one;'
> If the type is 2 (type=2) I want to return 'SELECT data FROM two;'

If you don't need to do updates, you can do this with a view.
It would look something like:

CREATE VIEW number (data, type) AS SELECT one.data, 1 FROM one UNION
SELECT two.data, 2 FROM two;

I didn't test the command so there might be a syntax error in it, but
the approach should work.

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