From: Leif Biberg Kristensen <leif@solumslekt.org>
To: pgsql-sql@postgresql.org
Subject: Re: Need a help in regexp
Date: Thu, 6 May 2010 17:37:52 +0200
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On Thursday 6. May 2010 16.48.26 Nicholas I wrote:
> Hi,
> 
> Need a help in regexp!
> 
> I have a table in which the data's are entered like,
> 
> Example:
> 
> One (1)
> Two (2)
> Three (3)
> 
> I want to extract the data which is only within the parentheses.
> 
> that is
> 1
> 2
> 3
> 
> i have written a query,
> *select regexp_matches(name,'([^(]+)([)]+)','g') from table;*
> which outputs the data as,
> {"test"}
> {"test2"}

If what you've got inside the parentheses always is an integer, and it's 
always the only or first integer in the string, you can use:

SELECT (REGEXP_MATCHES(bar, E'(\\d+)'))[1] FROM foo;

You can even cast it to an integer on the fly:

SELECT (REGEXP_MATCHES(bar, E'(\\d+)'))[1]::INTEGER FROM foo;

Or as a more general case, whatever's inside (the first) set of parentheses:

SELECT (REGEXP_MATCHES(bar, E'\\((.+?)\\)'))[1] FROM foo;

regards,
-- 
Leif Biberg Kristensen
http://solumslekt.org/blog/