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Aggregation Commands¶
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注解
For details on specific operator, including syntax and examples, click on the specific operator to go to its reference page.
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 | Deprecated. Groups documents in a collection by the specified key and performs simple aggregation. |
| mapReduce | Performs map-reduce aggregation for large data sets. |
Aggregation Methods¶
| Name | Description |
|---|---|
| db.collection.aggregate() | Provides access to the aggregation pipeline. |
| db.collection.group() | Deprecated. Groups documents in a collection by the specified key and performs simple aggregation. |
| db.collection.mapReduce() | Performs map-reduce aggregation for large data sets. |