[ARROW-12319] [Rust][DataFusion] Improve the errors that result when a aggregate type is not supported

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Invalid
• Component/s: Rust - DataFusion
• External issue URL: https://github.com/apache/arrow/issues/28121
• Assignee: Unassigned
• Reporter: Andrew Lamb
• Created: 09/Apr/21 21:11
• Updated: 11/Jan/23 08:25
• Resolved: 26/Apr/21 13:33

Description

When you try and run a query such as

select AVG(ts_colum) from t;

where ts_column has `DataType::Timestamp` type, you get a pretty unintelligible error message

"Coercion from [Timestamp(Nanosecond, None)] to the signature Uniform(1, [Int8, Int16, Int32, Int64, UInt8, UInt16, UInt32, UInt64, Float32, Float64]) failed."

This error should be improved to say something more like "AVG is not supported for

{datatype}

try an explicit cast."