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Aggregation Commands

Name Description
aggregate Performs aggregation tasks such as group using the aggregation framework.
count Counts the number of documents in a collection.
distinct Displays the distinct values found for a specified key in a collection.
group Groups documents in a collection by the specified key and performs simple aggregation.
mapReduce Performs map-reduce aggregation for large data sets.

For a detailed comparison of the different approaches, see Aggregation Commands Comparison.