The fields to aggregate on, and the names they should be aggregated under.
the sequence of operators specifying aggregate calculation
(groupMulti: StringAdd).self
(groupMulti: StringFormat).self
(Since version 0.20.3) No longer a case class
(Since version 0.20.3) No longer a case class
(Since version 0.20.3) No longer a case class
(groupMulti: ArrowAssoc[GroupMulti]).x
(Since version 2.10.0) Use leftOfArrow
instead
(groupMulti: Ensuring[GroupMulti]).x
(Since version 2.10.0) Use resultOfEnsuring
instead
$groups documents together to calculate aggregates on document collections. This command aggregates on multiple fields, and they must be named.