Re: Generate a empty Aggregate after RelFieldTrimmer#trim

[Julian Hyde]

I agree with you that a LogicalAggregate with no fields is problematic. This is 
the topic of https://issues.apache.org/jira/browse/CALCITE-4317 
<https://issues.apache.org/jira/browse/CALCITE-4317>. Let’s continue discussion 
there.

Julian

> On Oct 20, 2020, at 8:29 PM, JiaTao Tao <taojia...@gmail.com> wrote:
> 
> Hi fellows
> I found this in my plan, after RelFieldTrimmer#trim,
> `relBuilder.aggregate(groupKey,
> newAggCallList);`, the groupKey and newAggCallList are all empty, I think
> it doesn't meet expectations.
> 
> LogicalAggregate(group=[{}])
>  LogicalAggregate(group=[{0, 1, 2}])
> 
> 
> Regards!
> 
> Aron Tao