Luca Ferrari <fluca1978@gmail.com> writes:
> I'm wondering why in COPY TO (file or program) I cannot use generated
> columns: since I'm pushing data out of the table, why they are not
> allowed?
There's a comment about that in copy.c:
* We don't include generated columns in the generated full list and we don't
* allow them to be specified explicitly. They don't make sense for COPY
* FROM, but we could possibly allow them for COPY TO. But this way it's at
* least ensured that whatever we copy out can be copied back in.
Not sure how convincing that reasoning is, but it was at least
thought about. I do agree with it as far as the default column
list goes, but maybe we could allow explicit selection of these
columns in COPY TO.
regards, tom lane