Lesson 58/100

Tutorials MongoDB Tutorial

$bucket

$bucket: free step-by-step lesson with examples, common mistakes, and interview tips — part of MongoDB Tutorial on Toolliyo Academy.

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MongoDB Tutorial · Lesson 58 of 100

$bucket

Foundations & CRUD ✓Queries & Schema ✓Aggregation & ScaleAtlas & Projects

Aggregation & Scale · 3 — Pipelines · ~10 min · MongoDB — Aggregation Pipelines

What is this?

$bucket groups documents into numeric or value ranges you define — like price bands 0–999, 1000–4999, 5000+. Related: $bucketAuto for automatic boundaries.

Why should you care?

Product analytics and age demographics need histograms, not raw row dumps.

See it live — copy this example

Open mongosh or MongoDB Compass, select database nosqlverse, then run the example. Change one field and run again.

db.products.insertMany([
  { name: "A", price: 500 },
  { name: "B", price: 1500 },
  { name: "C", price: 7000 },
  { name: "D", price: 2500 }
])
db.products.aggregate([
  { $bucket: {
      groupBy: "$price",
      boundaries: [0, 1000, 5000, 10000],
      default: "other",
      output: { count: { $sum: 1 }, products: { $push: "$name" } }
  }}
])

Run Example »

Edit the code below and click Run to see the result in Toolliyo’s live editor.

Code
Result

What happened?

  • Prices fall into [0,1000), [1000,5000), [5000,10000).
  • Each bucket outputs count and product names.
  • default catches values outside boundaries.

Practice next

  1. Run the $bucket pipeline.
  2. Change boundaries and re-run.
  3. Try $bucketAuto with buckets: 3.
  4. Bucket orders by total for AOV bands.
  5. Output avgPrice with $avg.

Remember

$bucket builds histograms. boundaries define ranges. output customizes bucket fields.

Price band assortment

Category managers see how many SKUs sit in budget vs premium bands.

Outcome: Assortment gaps become visible quickly.

Interview prep for this lesson

Practice these questions aloud after reading—each links to a full structured answer.

Junior Detailed
Explain SQL queries in the context of MongoDB.
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. How to structure your answer (60–90 seconds) Define SQL queries in plain languag…
Mid Detailed
What are common mistakes teams make with Schema design when using MongoDB?
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. How to structure your answer (60–90 seconds) Define Schema design in plain langu…
Senior Detailed
How would you debug a production issue related to Transactions in a MongoDB application?
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. How to structure your answer (60–90 seconds) Define Transactions in plain langua…
Mid Detailed
Compare two approaches to Indexing—when would you choose each?
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. How to structure your answer (60–90 seconds) Define Indexing in plain language f…
Junior Detailed
Describe a real-world scenario where Normalization mattered in a MongoDB project.
Short answer: Interviewers want a crisp definition, a practical example from your projects, and awareness of trade-offs—not textbook dumps. How to structure your answer (60–90 seconds) Define Normalization in plain langu…
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MongoDB Tutorial
Course syllabus

MongoDB Tutorial

MongoDB — Foundations
MongoDB — CRUD Operations
MongoDB — Query Operators
MongoDB — Schema Design
MongoDB — Indexing & Performance
MongoDB — Aggregation Pipelines
MongoDB — Replication & Sharding
MongoDB — Atlas & Security
MongoDB — Modern Features
MongoDB — Real-World Projects
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