any_value
Description
Returns any non-null value from the specified expression within a group. If no expression is provided, it defaults to the $d
object.
Returns null
if all values in the group are null
.
Syntax
Arguments
Name | Type | Required | Description |
---|---|---|---|
expression | any | false | Expression to evaluate. Defaults to $d . |
Example
Description
Use case: Select any non-null username from a group of documents
Suppose you want to group documents by team and retrieve any available username.
Example logs
{
"userId": 1,
"team": "A Team",
"username": null
},
{
"userId": 2,
"team": "A Team",
"username": "Ryan"
},
{
"userId": 3,
"team": "A Team",
"username": "Anastasia"
}
Example query
Example output
The output may vary depending on the order in which documents are processed:
Theme
Light