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* select by groups
@ 2004-03-01 22:20 Martin Marques <martin@bugs.unl.edu.ar>
2004-03-01 22:32 ` Re: select by groups Manuel Sugawara <masm@fciencias.unam.mx>
0 siblings, 1 reply; 2+ messages in thread
From: Martin Marques @ 2004-03-01 22:20 UTC (permalink / raw)
To: pgsql-sql
I have a table with names of people, email address, etc, and an identifier
that tells me which group they are in (could be a 1, 2, or 3 person group).
Is it posible to make a query that would give me the name of the persons of
each group in one row? Or do I have to do PL?
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Martín Marqués | select 'mmarques' || '@' || 'unl.edu.ar'
Centro de Telematica | DBA, Programador, Administrador
Universidad Nacional
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^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: select by groups
2004-03-01 22:20 select by groups Martin Marques <martin@bugs.unl.edu.ar>
@ 2004-03-01 22:32 ` Manuel Sugawara <masm@fciencias.unam.mx>
0 siblings, 0 replies; 2+ messages in thread
From: Manuel Sugawara @ 2004-03-01 22:32 UTC (permalink / raw)
To: Martin Marques <martin@bugs.unl.edu.ar>; +Cc: pgsql-sql
Martin Marques <martin@bugs.unl.edu.ar> writes:
> I have a table with names of people, email address, etc, and an identifier
> that tells me which group they are in (could be a 1, 2, or 3 person group).
> Is it posible to make a query that would give me the name of the persons of
> each group in one row? Or do I have to do PL?
Use GROUP BY with an aggregator that concatenate the names. The
aggregator may be implemented in plpgsql, for instance:
CREATE OR REPLACE FUNCTION concat (text, text) RETURNS text
AS 'select case when $1 = '''' then $2 else ($1 || '', '' || $2) end'
LANGUAGE sql;
CREATE AGGREGATE concat (
BASETYPE = text,
SFUNC = public.concat,
STYPE = text,
INITCOND = ''
);
Regards,
Manuel.
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2004-03-01 22:20 select by groups Martin Marques <martin@bugs.unl.edu.ar>
2004-03-01 22:32 ` Manuel Sugawara <masm@fciencias.unam.mx>
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