[ARROW-12318] [Rust][DataFusion] Add support for AVG(Timestamp) types

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Invalid
• Component/s: Rust - DataFusion
• External issue URL: https://github.com/apache/arrow/issues/28120
• Assignee: Unassigned
• Reporter: Andrew Lamb
• Created: 09/Apr/21 21:07
• Updated: 11/Jan/23 08:25
• Resolved: 26/Apr/21 13:33

Description

This is a follow on to ARROW-12277

Background: Support for Min/Max/Sum/Count were added for DataType::Timestamp types in https://github.com/apache/arrow/pull/9970.

This ticket tracks adding support for Avg, which is slightly more involved as currently Avg assumes the output type is always F64, and in this case I think Avg(timestamp) should also be (timestamp). We should double check what postgres does in this case and follow its example