MongoDB $nin: Not In Operator

Summary: in this tutorial, you’ll learn about the MongoDB $nin (Not In) operator and how to apply it effectively.

Introduction to the MongoDB $nin operator

The $nin is a query comparison operator that allows you to find documents where:

• the value of the field is not equal to any value in an array
• or the field does not exist.

Here is the syntax of the $nin operator:

{ field: { $nin: [ <value1>, <value2> ...]} }

Like the $in operator, the value list (<value1>, <value2>,…) can be a list of literal values or regular expressions.

MongoDB $nin operator examples

We’ll use this products collections:

db.products.insertMany([
    { "_id" : 1, "name" : "xPhone", "price" : 799, "releaseDate": ISODate("2011-05-14"), "spec" : { "ram" : 4, "screen" : 6.5, "cpu" : 2.66 },"color":["white","black"],"storage":[64,128,256]},
    { "_id" : 2, "name" : "xTablet", "price" : 899, "releaseDate": ISODate("2011-09-01") , "spec" : { "ram" : 16, "screen" : 9.5, "cpu" : 3.66 },"color":["white","black","purple"],"storage":[128,256,512]},
    { "_id" : 3, "name" : "SmartTablet", "price" : 899, "releaseDate": ISODate("2015-01-14"), "spec" : { "ram" : 12, "screen" : 9.7, "cpu" : 3.66 },"color":["blue"],"storage":[16,64,128]},
    { "_id" : 4, "name" : "SmartPad", "price" : 699, "releaseDate": ISODate("2020-05-14"),"spec" : { "ram" : 8, "screen" : 9.7, "cpu" : 1.66 },"color":["white","orange","gold","gray"],"storage":[128,256,1024]},
    { "_id" : 5, "name" : "SmartPhone", "price" : 599,"releaseDate": ISODate("2022-09-14"), "spec" : { "ram" : 4, "screen" : 5.7, "cpu" : 1.66 },"color":["white","orange","gold","gray"],"storage":[128,256]}
 ])

1) Using the MongoDB $nin opeator to match values

The following query uses the $nin operator to select documents from the products collection where the price is neither 599 or 799:

db.products.find({
    price: {
        $nin: [699, 799]
    }
}, {
    name: 1,
    price: 1
})

It returned the following documents:

{ "_id" : 2, "name" : "xTablet", "price" : 899 }
{ "_id" : 3, "name" : "SmartTablet", "price" : 899 }
{ "_id" : 5, "name" : "SmartPhone", "price" : 599 }

2) Using the MongoDB $nin operator to match values in an array

The following example uses the $nin operator to select documents where the color array doesn’t have an element that is either "black" or "white":

db.products.find({
    color: {
        $nin: ["black", "white"]
    }
}, {
    name: 1,
    color: 1
})

The query returned the following documents:

{ "_id" : 3, "name" : "SmartTablet", "color" : [ "blue" ] }

3) Using the MongoDB $nin operator with regular expressions

The following query uses the $nin operator to find documents where the color array doesn’t have an element that matches /^g+/ and /^w+/ regular expression:

db.products.find({
    color: {
        $nin: [/^g+/, /^w+/]
    }
}, {
    name: 1,
    color: 1
})

It returned the following documents:

{ "_id" : 3, "name" : "SmartTablet", "color" : [ "blue" ] }

Summary

• Use the MongoDB $nin operator to select documents where the value of a field is not equal to any values in an array.
• The value list can contain literal values or regular expressions.