Richard, Andreas,

thank you very much for your solutions. I took a look on
both solutions, but I choosed Andreas's solution because
is shorter :)

So Andreas, would you please give some more explanations
on your solution? I didn't work with functions and aggregate till
now.

I don't understand how this comma_aggregate works. I can see that this
function it is defined with two arguments, but the aggredate it is called
with a single argument.

And what is LANGUAGE sql IMMUTABLE STRICT ?

CREATE FUNCTION comma_aggregate(text,text) RETURNS text AS '
SELECT CASE WHEN $1 <> '''' THEN $1 || '', '' || $2 ELSE $2 END; '
LANGUAGE sql IMMUTABLE STRICT;

CREATE AGGREGATE comma (basetype=text, sfunc=comma_aggregate, stype=text,
initcond='' );



Best regards,
     Loredana

Reply via email to