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Introduce return_data_type for Aggregate function #7960
Description
Is your feature request related to a problem or challenge?
return_data_type is not the same as the data_type for List case. For example, data_type: List(Int64), return_data_type will be Int64
Ref: https://github.com/apache/arrow-datafusion/pull/7242/files
Describe the solution you'd like
Introduce return_data_type for Sum, and other Aggregate function
Describe alternatives you've considered
No response
Additional context
No response
Activity
alamb commentedon Oct 29, 2023
I think we should do some more careful thinking of how to handle multi-phase aggregates where the intermediate type is not the same as the output type -- for example
SUM(x)for non lists can use the same aggregate (as you can sum partial sums) butCOUNT(x)does not -- the first phase must actually COUNT but the second needs to use SUM.This causes problems for #6937 where we might want to dynamically stop doing the first phase aggregation.
jayzhan211 commentedon Nov 12, 2023
TODO
jayzhan211 commentedon Jun 12, 2024
Reopen it if there is any concrete issue to solve