MongoDB $lte Operator

Posted in mongoDB Tutorial

Updated on Oct 31, 2024

By Mari Selvan

👁️ 26 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In MongoDB's aggregation framework, the $lte operator serves as a fundamental tool for filtering documents based on the condition that a field's value is less than or equal to a specified value. This operator proves to be invaluable in scenarios where you need to extract data that falls within a certain range.

Let's delve into the details of how the $lte operator functions within MongoDB's aggregation pipelines.

💡 Syntax

The syntax for the $lte method is straightforward:

syntax.js

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{ $lte: <value> }

$lte: This operator signifies that the subsequent operation will filter documents where the field value is less than or equal to the specified value.
<value>: This represents the value against which the field's value will be compared.

📝 Example

⌨️ Input

Consider a collection named students containing documents with fields name and age, representing student information. Here are sample documents from the students collection:

Input

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[
  { "_id": ObjectId("609c26812e9274a86871bc6a"), "name": "Alice", "age": 20 },
  { "_id": ObjectId("609c26812e9274a86871bc6b"), "name": "Bob", "age": 25 },
  { "_id": ObjectId("609c26812e9274a86871bc6c"), "name": "Charlie", "age": 18 }
]

🔄 Aggregation

Suppose we want to find students who are 20 years old or younger. Here's how you can achieve this using the $lte operator:

example.js

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db.students.aggregate([
  {
    $match: {
      age: { $lte: 20 }
    }
  }
])

🧩 Explanation

$match: This stage filters documents based on the specified condition.
$lte: Selects documents where the age field is less than or equal to 20.

When discussing how the above aggregation works:

The aggregation filters out documents where the "age" field is less than or equal to 20.
Two documents match this condition: Alice with an age of 20 and Charlie with an age of 18.
Bob is excluded from the output because his age (25) is not less than or equal to 20.

💻 Output

Now, let's take a look at the output generated by the aggregation pipeline:

Output

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{ "_id": ObjectId("609c26812e9274a86871bc6a"), "name": "Alice", "age": 20 }
{ "_id": ObjectId("609c26812e9274a86871bc6c"), "name": "Charlie", "age": 18 }

📚 Use Cases

Age Filtering:

The $lte operator is useful for filtering documents based on age or other numerical criteria, enabling users to extract subsets of data that meet specific requirements.
Date Filtering:

When working with date fields, the $lte operator can be employed to filter documents based on dates falling on or before a certain threshold.
Threshold Analysis:

In various analytical scenarios, the $lte operator facilitates the extraction of data points that fall below or equal to certain thresholds, aiding in threshold-based analysis.

🎉 Conclusion

The $lte operator in MongoDB's aggregation framework provides a powerful mechanism for filtering documents based on less than or equal to conditions, enabling users to extract subsets of data that meet specific criteria. Whether you're filtering by age, date, or numerical values, mastering the usage of $lte empowers you to efficiently retrieve relevant data from your MongoDB collections.

With its intuitive syntax and diverse applications, the $lte operator proves to be an indispensable asset for data filtering and analysis within MongoDB's aggregation framework. Incorporate it into your aggregation pipelines to unlock new possibilities in data extraction and gain deeper insights into your datasets.