Zeugswetter Andreas SB <ZeugswetterA@wien.spardat.at> writes:
>> Also, what happens if the specified length is less than zero? Error,
>> or is it treated as zero?
> Returns NULL in both if length <= 0. I would see the < 0 case as proper,
> but the == 0 case sure looks weird to me.
Since Oracle fails to distinguish NULL from empty string, it's hard to
tell what they have in mind here. I've implemented it as empty-string
result for length <= 0. You could possibly make a case for empty string
at length = 0 and NULL for length < 0, but I'm not sure it's worth the
trouble...
regards, tom lane