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Date: Tue, 30 Jul 2002 14:45:16 -0700 (PDT)
From: Stephan Szabo <sszabo@megazone23.bigpanda.com>
To: Josh Berkus <josh@agliodbs.com>
Cc: <pgsql-sql@postgresql.org>
Subject: Re: COUNT DISTINCT?
In-Reply-To: <200207301427.18815.josh@agliodbs.com>
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On Tue, 30 Jul 2002, Josh Berkus wrote:

> Folks,
>
> Anybody know a keen shortcut for the following:
>
> SELECT count(skip_date)
> FROM (SELECT DISTINCT skip_date FROM weekend_list
> 		WHERE ... ...) days_to_skip;
>
> That's a double aggregate, and is bound to be dog-slow.

Would that be the same as:
select count(distinct skip_date) from weekend_list
 where ...