[ARROW-15609] [C++][Compute] Support hash_aggregate with only keys

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 8.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/31071
• Assignee: Chenxi Li
• Reporter: Chenxi Li
• Created: 08/Feb/22 09:14
• Updated: 11/Jan/23 11:38
• Resolved: 16/Feb/22 19:10

Description

Currently, hash_aggregate requires keys, arguments and aggregation function, sometimes a user wants to execute group by without any aggregation functions.

Issue Links

• is depended upon by: ARROW-15719 [R] Simplify code for handling summarise() with no aggregations
• links to: GitHub Pull Request #12369