From: Josh Berkus <josh@agliodbs.com>
Organization: Aglio Database Solutions
To: Kai Hessing <kai.hessing@hobsons.de>
Subject: Re: can a function return a virtual table?
Date: Sat, 23 Apr 2005 11:00:56 -0700
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Kai,

> It would be much nicer to have to write something like: SELECT xyz, abc
> FROM active(tablex); where the function 'active(x)' returns a virtual
> table with all entries from table x where status is > -1. But sadly I
> have no idea how write such a function. Good old O'reilly can't help (or
> i'm to dumb *g*).

http://techdocs.postgresql.org/guides/SetReturningFunctions

Beware, though, that query plan estimation for SRFs is less accurate than for 
regular subqueries, so you could end up with unnecessarily slow query 
execution.  Test!

-- 
Josh Berkus
Aglio Database Solutions
San Francisco