How to get the last N records in mongodb?

📜 MongoDB: How to Get the Last N Records

Hey there, tech enthusiasts! 👋 Are you struggling with getting the last N records in MongoDB? Don't worry, you're not alone! This is a common issue that many developers face, but fear not - I've got you covered! In this blog post, I'll walk you through easy solutions and provide code examples to help you retrieve the desired data. So, let's dive right in! 💪

The Problem 🤔

By default, the MongoDB find() operation retrieves records from the beginning, making it a bit tricky to fetch the last N records. Additionally, if you want the result ordered from less recent to most recent, you're in for an extra challenge. That's a lot to tackle, but don't fret! I've got some amazing solutions for you. 💡

Solution 1: Use sort() and limit() 🗂️

The first approach involves combining the sort() and limit() methods to fetch the last N records:

db.collection.find().sort({ _id: -1 }).limit(N)

In the above code snippet, replace collection with the actual name of your collection and N with the number of records you wish to retrieve. By sorting the records in descending order based on their unique _id using -1, we ensure that the most recent entries appear first. The limit() method restricts the result to the specified number, giving you the last N records you desire. 📃

Solution 2: Utilize count() and skip() 😎

Another approach involves using count() to determine the total number of records, and then applying skip() to retrieve the required documents:

const totalCount = db.collection.count();
const skipCount = totalCount - N;

db.collection.find().skip(skipCount);

In the code snippet above, we first calculate totalCount by using the count() function on the collection. We then compute the skipCount by subtracting the desired number of records (N) from the totalCount. Finally, by utilizing skip() in conjunction with find(), we can retrieve the last N records without explicitly sorting them. 🧮

Solution 3: Leverage aggregate() 🔄

If you're seeking a more robust solution, aggregate() is here to save the day! We can leverage the $sort and $limit aggregation operators to fetch the last N records:

db.collection.aggregate([
  { $sort: { _id: -1 } },
  { $limit: N }
]);

In the code snippet above, the aggregation pipeline utilizes $sort to sort the records based on their _id in descending order. Next, $limit is applied, restricting the result to the specified number (N) and giving us our desired output. 🌪️

Engage and share your experience! 📣

There you have it! Three simple yet effective solutions to get the last N records in MongoDB. Give them a try, and let me know your thoughts! Have any other strategies or questions? Share your experience in the comments section below. Your feedback could help fellow developers facing similar challenges! 👇

Keep exploring, keep coding! 💻✨