The last argument in the aggregate compilation is a vec of keys the aggregate should be grouped by. We need to remove the symbol that is used in the aggregation fn from the binding to extract the grouping keys. As one may be grouping by the same key one is aggregating (even though that does not result in really meaningful results) we need to only remove one symbol, s.t. we still group by the aggregation fns symbol.
The last argument in the aggregate compilation is a vec of keys the aggregate should be grouped by. We need to remove the symbol that is used in the aggregation fn from the binding to extract the grouping keys. As one may be grouping by the same key one is aggregating (even though that does not result in really meaningful results) we need to only remove one symbol, s.t. we still group by the aggregation fns symbol.