From: | "Dan Langille" <dan(at)langille(dot)org> |
---|---|
To: | Josh Berkus <josh(at)agliodbs(dot)com> |
Cc: | pgsql-sql(at)postgresql(dot)org |
Subject: | Re: Removing simliar elements from a set |
Date: | 2003-09-27 12:38:27 |
Message-ID: | 3F754C83.22347.29465C5B@localhost |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-sql |
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/
From | Date | Subject | |
---|---|---|---|
Next Message | shengqj | 2003-09-27 12:47:29 | help |
Previous Message | Josh Berkus | 2003-09-26 23:55:13 | Re: Removing simliar elements from a set |