This version of the documentation is archived and no longer supported.

Pipeline Aggregation Operators

Name Description
$project Reshapes a document stream. $project can rename, add, or remove fields as well as create computed values and sub-documents.
$match Filters the document stream, and only allows matching documents to pass into the next pipeline stage. $match uses standard MongoDB queries.
$limit Restricts the number of documents in an aggregation pipeline.
$skip Skips over a specified number of documents from the pipeline and returns the rest.
$unwind Takes an array of documents and returns them as a stream of documents.
$group Groups documents together for the purpose of calculating aggregate values based on a collection of documents.
$sort Takes all input documents and returns them in a stream of sorted documents.
$geoNear Returns an ordered stream of documents based on proximity to a geospatial point.