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Mongoose Query.prototype.lt() API

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  • Last Updated : 27 Mar, 2023
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The Mongoose Query API lt() method is used to scan all the documents in a collection and return those whose path values are less than that passed in the method’s argument.

Syntax:

Query.prototype.lt( path, val )

Parameters: It accepts the following parameters as mentioned above and described below:

  • path: It is a string that identifies the attribute name in the mongoose schema
  • val: It is a number that determines the maximum value to compare from all the documents’ path values

Return type: It returns a Query object as a response.

Creating node application And Installing Mongoose:

Step 1: Create a node application using the following command:

mkdir folder_name
cd folder_name
npm init -y
touch main.js

Step 2: After completing the Node.js application, Install the required module using the following command:

npm install mongoose

Example 1: In this example, we will use this method to return documents that have age less than “22”

Filename: main.js

Javascript




// Importing the module
const mongoose = require('mongoose')
 
// Creating the connection
    {
        dbName: 'event_db',
        useNewUrlParser: true,
        useUnifiedTopology: true
    }, err => err ? console.log(err)
        : console.log('Connected to database'));
 
let personSchema = new mongoose.Schema({
    name: {
        type: String,
    },
    age: {
        type: Number,
    }
});
 
let personsArray = [
    {
        name: 'Luffy',
        age: 20
    },
    {
        name: 'Nami',
        age: 20,
    },
    {
        name: 'Zoro',
        age: 35
    }
]
 
let Person = mongoose.model('Person', personSchema);
 
(async () => {
    await Person.insertMany(personsArray)
    const res = await Person.find().where('age').lt(22);
    console.log({ res });
})();


Step to Run Application: Run the application using the following command from the root directory of the project:

node main.js

Output: 

 

GUI Representation of the  Database using MongoDB Compass:

 

Example 2: In this example, we will use this method to return documents that have an age less than “20”

Filename: main.js

Javascript




// Importing the module
const mongoose = require('mongoose')
 
// Creating the connection
    {
        dbName: 'event_db',
        useNewUrlParser: true,
        useUnifiedTopology: true
    }, err => err ? console.log(err)
        : console.log('Connected to database'));
 
let personSchema = new mongoose.Schema({
    name: {
        type: String,
    },
    age: {
        type: Number,
    }
});
 
let personsArray = [
    {
        name: 'Luffy',
        age: 20
    },
    {
        name: 'Nami',
        age: 20,
    },
    {
        name: 'Zoro',
        age: 35
    }
]
 
let Person = mongoose.model('Person', personSchema);
 
(async () => {
    await Person.insertMany(personsArray)
    const res = await Person.find().where('age').lt(20);
    console.log({ res });
})();


Step to Run Application: Run the application using the following command from the root directory of the project:

node main.js

Output:

 

GUI Representation of the  Database using MongoDB Compass:

 

Reference: https://mongoosejs.com/docs/api/query.html#query_Query-lt


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