Aggregation Variable Operators¶

注解

For details on specific operator, including syntax and examples, click on the specific operator to go to its reference page.

Name	Description
`$map`	Applies a subexpression to each element of an array and returns the array of resulting values in order. Accepts named parameters.
`$let`	Defines variables for use within the scope of a subexpression and returns the result of the subexpression. Accepts named parameters.

← $in (aggregation) $map (aggregation) →