Geoff Winkless <pgsqladmin@xxxxxxxx> writes: > SELECT COALESCE((SELECT 'Yes' FROM gwtest WHERE id=4), 'No') AS valid; > gives an error > I'm guessing this is because Postgres can't deduce the type of the > string column from the source when the result isn't returned. Oddly, > it also seems to cope when I do: > SELECT COALESCE((SELECT 'Yes'::varchar FROM gwtest WHERE id=4), 'No') AS valid Yup. The output column type of the sub-SELECT is determined without reference to its context, so there's nothing causing the unknown-type literal to get assigned a definite type. There's been occasional discussion of changing that behavior, but it's not real clear that it wouldn't create as many problems as it solves. 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
