Github user aljoscha commented on the pull request:
https://github.com/apache/flink/pull/1377#issuecomment-157728542
What it does now is to only pick one element in the group that has the
compound key of the `groupBy` expression. The reason why I did not want to
support this initially was that the element that results from this has
arbitrary values in the fields that are not key fields since only on arbitrary
element of the group of elements is picked.
Should we maybe limit this to only allow selecting fields that are also key
fields?
---
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.
---
