MongoDB $size Operator Examples
Let’s look at some examples of the $size operator in MongoDB to understand the operator better.
In the following examples, we are working with:
Database: w3wiki
Collection: arrayExample
Document: three documents that contain the details in the form of field-value pairs.
Using $size Operator example
In this example, we are going to find the size of the number1 field( whose value is an array) using a $size operator.
Query:
db.arrayExample.aggregate([
... {$match: {name: "Lolo"}},
... {$project: {number1Size: {$size: "$numbers1"}}}])
Output:
Using $size Operator in the Embedded Document example
In this example, we are going to find the size of the favGame.indoorGames field( whose value is an array) using a $size operator.
Query:
db.arrayExample.aggregate([
... {$match: {name: "Piku"}},
... {$project: {resultSize: {$size: "$favGame.indoorGames"}}}])
Output:
MongoDB $size Operator
MongoDB $size operator finds the total number of elements present in the specified array.
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