Re: COPY TO: provide hint when WHERE clause is used

Hi

On 19.08.25 03:35, torikoshia wrote:
> Considering what the user was trying to do, it might be helpful to
> provide a similar hint in this case as well.
> I’ve attached a patch that adds such a hint.
>
> What do you think?
>

+1

I tested the patch and the error message now has the intended HINT ...

postgres=# COPY t1 TO STDOUT WHERE i > 5;
ERROR:  WHERE clause not allowed with COPY TO
LINE 1: COPY t1 TO STDOUT WHERE i > 5;
                          ^
HINT:  Try the COPY (SELECT ... WHERE ...) TO variant.

... which aligns with the HINT from COPY TO from views

postgres=# COPY v1 TO STDOUT;
ERROR:  cannot copy from view "v1"
HINT:  Try the COPY (SELECT ...) TO variant.

Best, Jim