duplicate columns with COPY

Peter Eisentraut wrote:

Is there a reason why COPY TO STDOUT does not allow columns to be specified
more than once?

pei=# copy test1 (a, a) to stdout;
ERROR: 42701: column "a" specified more than once

Or is this just an overly extensive check that is actually intended for COPY
FROM STDIN?

You should be able to get around it with:

COPY (SELECT a , a FROM test1) TO stdout;

cheers

andew

Hi,

pei=# copy test1 (a, a) to stdout;
ERROR: 42701: column "a" specified more than once

Or is this just an overly extensive check that is actually intended for

COPY

FROM STDIN?

This seems to be a common check in both "COPY TO" and "COPY FROM" cases
source/destination being STDIN or otherwise. While it definitely makes sense
for the FROM case maybe we could relax this for the COPY TO case.

Regards,
Nikhils
--
EnterpriseDB http://www.enterprisedb.com

Peter Eisentraut <peter_e@gmx.net> writes:

Is there a reason why COPY TO STDOUT does not allow columns to be specified
more than once?

pei=# copy test1 (a, a) to stdout;
ERROR: 42701: column "a" specified more than once

Or is this just an overly extensive check that is actually intended for COPY
FROM STDIN?

I think it's reasonable even for COPY TO, since IMHO the odds that it's
a typo, rather than intentional, are probably 100:1.

As already noted, we do have a workaround if that is truly what you
intend.

regards, tom lane

Am Donnerstag, 20. Dezember 2007 schrieb Tom Lane:

I think it's reasonable even for COPY TO, since IMHO the odds that it's
a typo, rather than intentional, are probably 100:1.

ISTM that with this line of argument we could disable thousands of valid uses
of SQL commands.

--
Peter Eisentraut
http://developer.postgresql.org/~petere/