Re: duplicate columns with COPY

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