From: Dan Langille <dan@langille.org>
To: Josh Berkus <josh@agliodbs.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: Removing simliar elements from a set
Date: Sat, 27 Sep 2003 08:38:27 -0400
Message-ID: <3F754C83.22347.29465C5B@localhost> (raw)
In-Reply-To: <200309261655.13695.josh@agliodbs.com>
References: <20030926184440.B301@laptop.unixathome.org>
On 26 Sep 2003 at 16:55, Josh Berkus wrote:
> Dan,
>
> > I'm trying to remove items from a set which are similar to items in
> > another set.
> <snip>
>
> > In short, we remove all items from MASTER which are under the directories
> > specified in MATCHES.
>
> from your example, you are trying to remove all directories which do *not*
> match. What do you want, exactly?
Josh and I talked on IRC about this.
This is the result set I want:
/ports/Mk/bsd.python.mk
I want things from MASTER which do not match things in MATCHES.
Josh suggested this:
SELECT *
FROM master
WHERE NOT EXISTS (
SELECT *
FROM matches
WHERE master.pathname LIKE (matches.pathname || '/%'));
Cheers.
--
Dan Langille : http://www.langille.org/
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To: pgsql-sql@postgresql.org
Cc: dan@langille.org, josh@agliodbs.com
Subject: Re: Removing simliar elements from a set
In-Reply-To: <3F754C83.22347.29465C5B@localhost>
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