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. Explain a bit more How to structure your answer (60–90 seconds) Define SQL queri…
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. Explain a bit more How to structure your answer (60–90 seconds) Define Schema de…
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. Explain a bit more How to structure your answer (60–90 seconds) Define Transacti…
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. Explain a bit more How to structure your answer (60–90 seconds) Define Normaliza…
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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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