Message-ID: <4484445E.2000006@presinet.com>
Date: Mon, 05 Jun 2006 07:49:02 -0700
From: Bricklen Anderson <banderson@presinet.com>
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To: Mauro Bertoli <bertolima@yahoo.it>
CC: pgsql-sql@postgresql.org
Subject: Re: Get max value from an comma separated string
References: <20060529112238.61079.qmail@web27009.mail.ukl.yahoo.com>
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Mauro Bertoli wrote:
> Hi, I've a field that contain values-comma-separated
> like
> A) 1;2;3;;5  -- ;2;;4;5
> but also
> B) 12;34;18
> how I can get the max value?
> For A I tried:
> SELECT max(array_upper(string_to_array(answer,';'),1))
> FROM values;
> and work fine, but for B case I don't find a solution
> like
> SELECT max(string_to_array(answer,';')) FROM values;
> 
> Any ideas?
> Thanks for any hint
> 
You could try rearranging the values into rows, like so:

CREATE OR REPLACE FUNCTION text2rows (TEXT,TEXT) RETURNS SETOF TEXT AS $$
SELECT (string_to_array($1, $2))[x.i]
FROM generate_series(1,array_upper(string_to_array($1,$2),1)) AS x(i);
$$ language sql strict;

select max(val)
from (SELECT text2rows(answer,';') as val FROM answer) as t;