any BSON value acceptable by mongodb as identifier
the sequence of operators specifying aggregate calculation
any BSON value acceptable by mongodb as identifier
(group: StringAdd).self
(group: StringFormat).self
(group: ArrowAssoc[Group]).x
(Since version 2.10.0) Use leftOfArrow
instead
(group: Ensuring[Group]).x
(Since version 2.10.0) Use resultOfEnsuring
instead
Groups documents together to calulate aggregates on document collections. This command aggregates on arbitrary identifiers. Document fields identifier must be prefixed with
$
. http://docs.mongodb.org/manual/reference/aggregation/group/#_S_groupany BSON value acceptable by mongodb as identifier
the sequence of operators specifying aggregate calculation