MongoDB Query Language (MQL) Accumulators Operators
$avg
Computes the average of numeric values for documents in a group, bucket, or window.
$bottom
The $bottom operator returns the last document from the query's result set sorted by one or more fields
$bottomN
The $bottomN operator returns the last N documents from the result sorted by one or more fields
$count
The `$count` operator is used to count the number of documents that match a query filtering criteria.
$first
The $first operator returns the first value in a group according to the group's sorting order.
$firstN
The $firstN operator sorts documents on one or more fields specified by the query and returns the first N document matching the filtering criteria
$last
The $last operator returns the last document from the result sorted by one or more fields
$lastN
The $lastN accumulator operator returns the last N values in a group of documents.
$max
The $max operator returns the maximum value from a set of input values.
$maxN
Retrieves the top N values based on a specified filtering criteria
$median
The $median operator calculates the median value of a numeric field in a group of documents.
$min
Retrieves the minimum value for a specified field
$minN
Retrieves the bottom N values based on a specified filtering criteria
$percentile
The $percentile operator calculates the percentile of numerical values that match a filtering criteria
$stddevpop
The $stddevpop operator calculates the standard deviation of the specified values
$stddevsamp
The $stddevsamp operator calculates the standard deviation of a specified sample of values and not the entire population
$sum
The $sum operator calculates the sum of the values of a field based on a filtering criteria
$top
The $top operator returns the first document from the result set sorted by one or more fields
$topN
The $topN operator returns the first N documents from the result sorted by one or more fields