[FLINK-1408] Add group sorting with expression key

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Invalid
• Affects Version/s: 0.9
• Component/s: API / Scala
• Assignee: Unassigned
• Reporter: Fabian Hueske
• Created: 15/Jan/15 17:30
• Updated: 28/Feb/19 14:29
• Resolved: 15/Jan/15 17:33

Description

Currently groups can only be sorted using field indexes (for tuples) and key selection function.

persons.groupBy("name").sortGroup("age", Order.DESCENDING).groupReduce(do-something-here);

Would be good to allow group sorting also with field expressions for Pojos.