Github user yhuai commented on the pull request:
https://github.com/apache/spark/pull/9705#issuecomment-157156858
@JihongMA, @mengxr @marmbrus and I had a offline discussion. If all input
values are nulls or there is no input, we should return `null` (except count,
which returns 0). Basically, it is good to follow SQL. For std, if we have a
single non-null input value, we should return nan. Sorry for not defining it
clearly before.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
