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From: Vik Fearing <vik.fearing@dalibo.com>
To: James Cloos <cloos@jhcloos.com>
To: pgsql-sql@postgresql.org
Subject: Re: matching column of regexps
Date: Sun, 18 May 2014 20:35:02 -0400
Message-ID: <537951B6.4070202@dalibo.com> (raw)
In-Reply-To: <m3wqdi649f.fsf@carbon.jhcloos.org>
References: <m3wqdi649f.fsf@carbon.jhcloos.org>
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On 05/18/2014 07:44 PM, James Cloos wrote:
> Is there a better way to answer the question, "Do ANY rows match?"
> without having to return the list of matching rows?  I didn't find
> anything googling.

select exists (select 1 from retest where active is true and ? ~ re);


> Is there a way to index such a table/query?

There are several ways to index such a query.  If there are very many
rows but with only a few being active, then a partial index will do wonders.

http://www.postgresql.org/docs/current/static/indexes-partial.html

Otherwise, it is possible to use an index for regular expressions using
the pg_trgm extension.

http://www.postgresql.org/docs/current/static/pgtrgm.html

-- 
Vik



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