Re: COPY for CSV documentation

On Mon, Apr 12, 2004 at 10:30:22 -0400,
  Bruce Momjian <pgman@candle.pha.pa.us> wrote:
>
> It is my understanding that \N is a valid column value (no backslash
> escape in CSV, right?), so we can't use it for NULL.
> The only thing I can think of is for NULL to be:
>
>     ,,
>
> (no quotes) and a zero-length string to be:
>
>     ,"",
>
> How do most applications handle those two cases?  If they accept either,
> can we use that so we can read our own CSV files without losing the NULL
> specification?

I think the above are going to be treated as equvialent by most CSV parsers.

There doesn't seem to be a standard for CSV. From what I found describing
it, there isn't any feature for distinguishing NULLs from empty strings.
So whatever gets done is going to be application specific.