Groups documents together to calulate 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
idField
Fields to aggregate on, and the names they should be aggregated under.
ops
Sequence of operators specifying aggregate calculation.
Groups documents together to calulate 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
Fields to aggregate on, and the names they should be aggregated under.
Sequence of operators specifying aggregate calculation.