MongoDB $mod Operator

MongoDB provides different types of arithmetic expression operators that are used in the aggregation pipeline stages and $mod operator is one of them. This operator is used to divide one number by another number and return the remainder.

Syntax: 

{ $mod: [ <expression1>, <expression2> ] }

Here, in this operator, the arguments passed in an array. It takes two arguments, the first argument is the dividend and the second argument is the divisor.  The arguments must be a valid expression until it resolves to a number. 

Examples:

In the following examples, we are working with:

Database: GeeksforGeeks

Collection: example

Document: two documents that contain the details of the shapes in the form of field-value pairs.

Finding reminder using $mod operator: 

In this example, we are going to find the remainder by dividing the value(i.e., 4) of the side field by 2 using $mod operator.

db.example.aggregate([{$match:{name: "Square"}},
... {$project: {remainderValue: {$mod: ["$side", 2]}}}])

Finding reminder in the embedded document using $mod operator:

In this example, we are going to find the remainder by dividing the value(i.e., 15) of the measurement.width field by the value(i.e., 10) of measurement.height field using $mod operator.

db.example.aggregate([{$match:{name: "Rectangle"}},
... {$project: {remainderValue: {$mod: ["$measurement.width", 
                                        "$measurement.height"]}}}])