From: | "Andrew G(dot) Hammond" <drew(at)xyzzy(dot)dhs(dot)org> |
---|---|
To: | Louis-David Mitterrand <vindex(at)apartia(dot)org> |
Cc: | pgsql-sql(at)postgresql(dot)org |
Subject: | Re: return a text agreggate from a subselect |
Date: | 2001-12-19 19:28:49 |
Message-ID: | 1008790130.855.21.camel@xyzzy |
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Thread: | |
Lists: | pgsql-sql |
On Wed, 2001-12-19 at 11:11, Louis-David Mitterrand wrote:
> The subselect: (SELECT company_name FROM table)
>
> The output I'd like: 'Company1|Company2|Company3|etc.'
>
> Should I write a function or a new agreggate for this or is there is
> simpler way?
I'm afraid the cleanest way to do this is with an aggregate.
CREATE FUNCTION barjoin(text, text) RETURNS text AS '
SELECT CASE WHEN length($1) > 0 THEN $1 || ''|'' || $2
ELSE $2 END;' LANGUAGE 'sql';
CREATE AGGREGATE barconcat(basetype=text, sfunc=barjoin,
stype=text, initcond='');
SELECT barconcat(company_name) FROM table;
If you're in the mood to pointlessly performance tune the snot out of
it, you could implement barjoin to simply do $1|$2, and then write a
final function for the aggregate that trimmed off the beginning |...
--
Andrew G. Hammond mailto:drew(at)xyzzy(dot)dhs(dot)org
http://xyzzy.dhs.org/~drew/
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"To blow recursion you must first blow recur" -- me
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