MongoDB Query Language (MQL) Aggregation Operators
Aggregation operators process and transform data within aggregation pipelines. These operators enable you to perform complex data manipulations, including grouping, filtering, reshaping, and computing derived values from your document collections.
$addFields
The $addFields stage in the aggregation pipeline is used to add new fields to documents.
$bucket
Groups input documents into buckets based on specified boundaries.
$changeStream
The $changeStream stage opens a change stream cursor to track data changes in real-time.
$collStats
The $collStats stage in the aggregation pipeline is used to return statistics about a collection.
$convert
The $convert operator converts an expression into the specified type
$densify
Adds missing data points in a sequence of values within an array or collection.
$documents
The $documents stage creates a pipeline from a set of provided documents.
$facet
The $facet allows for multiple parallel aggregations to be executed within a single pipeline stage.
$fill
The $fill stage allows filling missing values in documents based on specified methods and criteria.
$geoNear
The $geoNear operator finds and sorts documents by their proximity to a geospatial point, returning distance information for each document.
$group
The $group stage groups documents by specified identifier expressions and applies accumulator expressions.
$indexStats
The $indexStats stage returns usage statistics for each index in the collection.
$isNumber
The $isNumber operator checks if a specified expression is a numerical type
$lookup
The $lookup stage in the Aggregation Framework is used to perform left outer joins with other collections.
$match
The $match stage in the aggregation pipeline is used to filter documents that match a specified condition.
$merge
The $merge stage in an aggregation pipeline writes the results of the aggregation to a specified collection.
$out
The `$out` stage in an aggregation pipeline writes the resulting documents to a specified collection.
$redact
Filters the content of the documents based on access rights.
$replaceWith
The $replaceWith operator in DocumentDB returns a document after replacing a document with the specified document
$sample
The $sample operator in DocumentDB returns a randomly selected number of documents
$set
The $set operator in DocumentDB updates or creates a new field with a specified value
$skip
The $skip stage in the aggregation pipeline is used to skip a specified number of documents from the input and pass the remaining documents to the next stage in the pipeline.
$sort
The $sort stage in the aggregation pipeline is used to order the documents in the pipeline by a specified field or fields.
$sortByCount
The $sortByCount stage in the aggregation pipeline is used to group documents by a specified expression and then sort the count of documents in each group in descending order.
$toBool
The $toBool operator converts an expression into a Boolean type
$toDate
The $toDate operator converts supported types to a proper Date object.
$toDecimal
The $toDecimal operator converts an expression into a Decimal type
$toDouble
The $toDouble operator converts an expression into a Double value
$toInt
The $toInt operator converts an expression into an Integer
$toLong
The $toLong operator converts an expression into a Long value
$toObjectId
The $toObjectId operator converts an expression into an ObjectId
$toString
The $toString operator converts an expression into a String
$unset
The $unset stage in the aggregation pipeline is used to remove specified fields from documents.
$unwind
The $unwind stage in the aggregation framework is used to deconstruct an array field from the input documents to output a document for each element.