Aggregations in MongoDB 2025/06/30 Mon - 11:13 PM
An aggregation in MongoDB is used when you want to:
- Group values from multiple documents together
- Perform operations on the grouped data to return a single result
- Analyze data changes over time
The best way of using aggregation is with aggregation pipelines, where you can have multiple stages. And in each stage you can process documents, from the docs:
- Each stage performs an operation on the input documents
- For example, a stage can filter documents, group documents, and calculate values.
- The documents that are output from a stage are passed to the next stage.
- An aggregation pipeline can return results for groups of documents.
- For example, return the total, average, maximum, and minimum values.