| sidebar_position |
|---|
2 |
Aggregation stages are a series of one or more processes in a pipeline that acts upon the returned result of the previous stage, starting with the input documents.
| Supported aggregation stages | Description |
|---|---|
$count |
Returns the count of all matched documents in a specified query |
$group |
Groups documents based on specific value or expression and returns a single document for each group |
$limit |
Limits specific documents and passes the rest to the next stage |
$match |
Acts as a find operation by only returning documents that match a specified query to the next stage |
$project |
Specifies the fields in a document to pass to the next stage in the pipeline |
$skip |
Skips a specified n number of documents and passes the rest to the next stage |
$sort |
Sorts and returns all the documents based on a specified order |
$unset |
Specifies the fields to be removed/excluded from a document |
$unwind |
Deconstructs and returns a document for every element in an array field |