Groups documents together to calculate aggregates on document collections.
This command aggregates on multiple fields, and they must be named.
http://docs.mongodb.org/manual/reference/aggregation/group/#_S_group
idFields
The fields to aggregate on, and the names they should be aggregated under.
ops
the sequence of operators specifying aggregate calculation
Groups documents together to calculate aggregates on document collections. This command aggregates on multiple fields, and they must be named. http://docs.mongodb.org/manual/reference/aggregation/group/#_S_group
The fields to aggregate on, and the names they should be aggregated under.
the sequence of operators specifying aggregate calculation