"Rhys A.D. Stewart" <rhys.stewart@xxxxxxxxx> writes: > I have an xml aggregate function that always returns 'ERROR: invalid > XML content'. However an identical function that uses text produces > valid xml with the same inputs. I believe the reason this doesn't work is that the aggregate's initial value is faulty: it's supposed to be an XML value and it isn't. regression=# select ''::xml; ERROR: invalid XML content LINE 1: select ''::xml; ^ It's unfortunate that the CREATE AGGREGATE command doesn't complain about that --- maybe we could improve it. As far as making a working aggregate goes, I'd try leaving off the initcond clause (so that the initial value is NULL) and then marking the transition function STRICT. (plays around with xmlconcat on nulls ...) hm, maybe you'd not even need the STRICT marking, though personally I'd suggest it. regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general