partitionedAggBy

The aggregation(s) to apply to the source table.

Whether to keep result rows for groups that are initially empty or become empty as a result of updates. Each aggregation operator defines its own value for empty groups.

A table whose distinct combinations of values for the groupByColumns should be used to create an initial set of aggregation groups. All other columns are ignored. This is useful in combination with preserveEmpty == true to ensure that particular groups appear in the result table, or with preserveEmpty == false to control the encounter order for a collection of groups and thus their relative order in the result. Changes to initialGroups are not expected or handled; if initialGroups is a refreshing table, only its contents at instantiation time will be used. If initialGroups == null, the result will be the same as if a table with no rows was supplied.

The names of the key columns to aggregate by.