MongoDB All Commands & Examples for Practice and Learning

(Complete Hands-On Guide – Copy, Paste, Run in mongosh)

MongoDB All Commands & Examples for Practice and Learning

(Complete Hands-On Guide – Copy, Paste, Run in mongosh)

Setup: Start MongoDB & Connect

# Start server (if not running)
mongod

# Open shell
mongosh

// Switch to practice database
use practiceDB

1. DATABASE COMMANDS

Command	Example
Create / Switch DB	`use practiceDB`
Show all DBs	`show dbs`
Current DB	`db`
Drop DB	`db.dropDatabase()`

// Practice
use practiceDB
db.dropDatabase()  // Clean start
show dbs

2. COLLECTION COMMANDS

// Create collection (implicit)
db.createCollection("users")

// List collections
show collections

// Drop collection
db.users.drop()

3. INSERT COMMANDS (CREATE)

Insert One

db.users.insertOne({
  name: "Alice",
  age: 25,
  city: "New York",
  hobbies: ["reading", "cycling"],
  active: true,
  joined: new Date()
})

Insert Many

db.users.insertMany([
  { name: "Bob", age: 30, city: "London", hobbies: ["gaming"], active: false },
  { name: "Charlie", age: 35, city: "Paris", hobbies: ["cooking", "tennis"], active: true },
  { name: "Diana", age: 28, city: "Tokyo", hobbies: ["painting"], active: true }
])

4. QUERY COMMANDS (READ)

Find All

db.users.find().pretty()

Find with Condition

db.users.find({ age: { $gt: 28 } }).pretty()
db.users.find({ city: "Paris" }).pretty()

Find One

db.users.findOne({ name: "Alice" })

Projection (Select fields)

db.users.find({}, { name: 1, city: 1, _id: 0 }).pretty()

Logical Operators

// AND
db.users.find({ age: { $gt: 25 }, active: true })

// OR
db.users.find({ $or: [{ city: "Tokyo" }, { age: 35 }] })

// NOT
db.users.find({ age: { $ne: 30 } })

Array Queries

// Has hobby "gaming"
db.users.find({ hobbies: "gaming" })

// Has multiple hobbies
db.users.find({ hobbies: { $all: ["cooking", "tennis"] } })

// Array size
db.users.find({ hobbies: { $size: 2 } })

// Element match
db.users.find({ "hobbies.0": "reading" })  // First hobby

Regex

db.users.find({ name: /^A/ })  // Starts with A
db.users.find({ name: /bob/i }) // Case-insensitive

5. UPDATE COMMANDS

Update One

db.users.updateOne(
  { name: "Alice" },
  { $set: { age: 26, city: "Boston" } }
)

Update Many

db.users.updateMany(
  { active: false },
  { $set: { active: true } }
)

Increment / Decrement

db.users.updateOne(
  { name: "Bob" },
  { $inc: { age: 1 } }
)

Push to Array

db.users.updateOne(
  { name: "Charlie" },
  { $push: { hobbies: "swimming" } }
)

Pull from Array

db.users.updateOne(
  { name: "Diana" },
  { $pull: { hobbies: "painting" } }
)

Replace Document

db.users.replaceOne(
  { name: "Bob" },
  { name: "Bobby", age: 31, city: "Berlin", active: true }
)

Upsert (Insert if not exists)

db.users.updateOne(
  { name: "Eve" },
  { $set: { age: 29, city: "Sydney" } },
  { upsert: true }
)

6. DELETE COMMANDS

Delete One

db.users.deleteOne({ name: "Eve" })

Delete Many

db.users.deleteMany({ active: false })

Drop Collection / DB

db.users.drop()
db.dropDatabase()

7. INDEX COMMANDS

// Single field
db.users.createIndex({ age: 1 })

// Compound
db.users.createIndex({ city: 1, age: -1 })

// Unique
db.users.createIndex({ email: 1 }, { unique: true })

// Text index
db.articles.createIndex({ title: "text", content: "text" })

// Partial index
db.users.createIndex(
  { age: 1 },
  { partialFilterExpression: { active: true } }
)

// Sparse
db.users.createIndex({ phone: 1 }, { sparse: true })

// TTL (auto-delete after 1 hour)
db.sessions.createIndex(
  { createdAt: 1 },
  { expireAfterSeconds: 3600 }
)

// List indexes
db.users.getIndexes()

// Drop index
db.users.dropIndex("age_1")

8. AGGREGATION PIPELINE EXAMPLES

Basic: Filter + Project

db.users.aggregate([
  { $match: { age: { $gte: 30 } } },
  { $project: { name: 1, age: 1, _id: 0 } }
])

Group & Count

db.users.aggregate([
  { $group: { _id: "$city", count: { $sum: 1 } } }
])

Average Age per City

db.users.aggregate([
  { $group: {
      _id: "$city",
      avgAge: { $avg: "$age" },
      totalUsers: { $sum: 1 }
  }}
])

Top 2 Cities by User Count

db.users.aggregate([
  { $group: { _id: "$city", count: { $sum: 1 } } },
  { $sort: { count: -1 } },
  { $limit: 2 }
])

Unwind Array

db.users.aggregate([
  { $unwind: "$hobbies" },
  { $group: { _id: "$hobbies", count: { $sum: 1 } } },
  { $sort: { count: -1 } }
])

Lookup (Join)

// Assume orders collection
db.users.aggregate([
  {
    $lookup: {
      from: "orders",
      localField: "name",
      foreignField: "customer",
      as: "orders"
    }
  },
  { $project: { name: 1, orderCount: { $size: "$orders" } } }
])

Add Computed Field

db.users.aggregate([
  {
    $addFields: {
      isAdult: { $gte: ["$age", 18] },
      hobbyCount: { $size: "$hobbies" }
    }
  }
])

Write Output to New Collection

db.users.aggregate([
  { $match: { active: true } },
  { $out: "active_users" }
])

9. SAMPLE DATA FOR PRACTICE

// Insert sample data
db.products.insertMany([
  { name: "Laptop", price: 1200, category: "Electronics", inStock: true, tags: ["portable", "work"] },
  { name: "Mouse", price: 25, category: "Electronics", inStock: true, tags: ["wireless"] },
  { name: "Book", price: 15, category: "Education", inStock: false, tags: ["paperback"] },
  { name: "Pen", price: 2, category: "Stationery", inStock: true, tags: ["blue", "ballpoint"] }
])

db.orders.insertMany([
  { orderId: "O1", customer: "Alice", items: ["Laptop", "Mouse"], total: 1225, status: "shipped" },
  { orderId: "O2", customer: "Bob", items: ["Book"], total: 15, status: "pending" }
])

10. PRACTICE EXERCISES (Try These!)

Find all users older than 28 from Tokyo
js db.users.find({ age: { $gt: 28 }, city: "Tokyo" })
Update all inactive users to active
js db.users.updateMany({ active: false }, { $set: { active: true } })
Count products in "Electronics" category
js db.products.countDocuments({ category: "Electronics" })
Get total sales per customer
js db.orders.aggregate([ { $group: { _id: "$customer", totalSpent: { $sum: "$total" } } } ])
Find products with "wireless" tag
js db.products.find({ tags: "wireless" })
Add index on price and sort descending
js db.products.createIndex({ price: -1 }) db.products.find().sort({ price: -1 })
Create TTL index on createdAt
js db.logs.createIndex({ createdAt: 1 }, { expireAfterSeconds: 86400 })

11. USEFUL SYSTEM COMMANDS

// Server status
db.serverStatus()

// Current operations
db.currentOp()

// Kill long-running op
db.killOp(<opId>)

// Collection stats
db.users.stats()

// Validate collection
db.users.validate()

// Compact (defragment)
db.runCommand({ compact: "users" })

12. MONGOSH TIPS

// Pretty print
.pretty()

// Limit results
.limit(5)

// Count
.count()

// Explain query plan
db.users.find({ age: 30 }).explain("executionStats")

// Clear screen
cls

// Exit
exit

Download This Guide as `.js` File

// Save as: mongodb-practice.js
// Run: mongosh mongodb-practice.js

use practiceDB
db.dropDatabase()

print("=== INSERTING DATA ===")
db.users.insertMany([...])  // paste all insert commands

print("=== PRACTICE QUERIES ===")
// paste all queries

Resources

You now have 100+ working MongoDB commands!
Copy → Paste → Run → Learn

Next Step: Build a mini project (e.g., Todo App, Blog, Inventory) using these commands.

Want a full project template or Node.js + MongoDB example? Just ask!

Last updated: Nov 12, 2025

MongoDB All Commands & Examples for Practice and Learning

(Complete Hands-On Guide – Copy, Paste, Run in mongosh)

MongoDB All Commands & Examples for Practice and Learning

(Complete Hands-On Guide – Copy, Paste, Run in mongosh)

Setup: Start MongoDB & Connect

# Start server (if not running)
mongod

# Open shell
mongosh

// Switch to practice database
use practiceDB

1. DATABASE COMMANDS

Command	Example
Create / Switch DB	`use practiceDB`
Show all DBs	`show dbs`
Current DB	`db`
Drop DB	`db.dropDatabase()`

// Practice
use practiceDB
db.dropDatabase()  // Clean start
show dbs

2. COLLECTION COMMANDS

// Create collection (implicit)
db.createCollection("users")

// List collections
show collections

// Drop collection
db.users.drop()

3. INSERT COMMANDS (CREATE)

Insert One

db.users.insertOne({
  name: "Alice",
  age: 25,
  city: "New York",
  hobbies: ["reading", "cycling"],
  active: true,
  joined: new Date()
})

Insert Many

db.users.insertMany([
  { name: "Bob", age: 30, city: "London", hobbies: ["gaming"], active: false },
  { name: "Charlie", age: 35, city: "Paris", hobbies: ["cooking", "tennis"], active: true },
  { name: "Diana", age: 28, city: "Tokyo", hobbies: ["painting"], active: true }
])

4. QUERY COMMANDS (READ)

Find All

db.users.find().pretty()

Find with Condition

db.users.find({ age: { $gt: 28 } }).pretty()
db.users.find({ city: "Paris" }).pretty()

Find One

db.users.findOne({ name: "Alice" })

Projection (Select fields)

db.users.find({}, { name: 1, city: 1, _id: 0 }).pretty()

Logical Operators

// AND
db.users.find({ age: { $gt: 25 }, active: true })

// OR
db.users.find({ $or: [{ city: "Tokyo" }, { age: 35 }] })

// NOT
db.users.find({ age: { $ne: 30 } })

Array Queries

// Has hobby "gaming"
db.users.find({ hobbies: "gaming" })

// Has multiple hobbies
db.users.find({ hobbies: { $all: ["cooking", "tennis"] } })

// Array size
db.users.find({ hobbies: { $size: 2 } })

// Element match
db.users.find({ "hobbies.0": "reading" })  // First hobby

Regex

db.users.find({ name: /^A/ })  // Starts with A
db.users.find({ name: /bob/i }) // Case-insensitive

5. UPDATE COMMANDS

Update One

db.users.updateOne(
  { name: "Alice" },
  { $set: { age: 26, city: "Boston" } }
)

Update Many

db.users.updateMany(
  { active: false },
  { $set: { active: true } }
)

Increment / Decrement

db.users.updateOne(
  { name: "Bob" },
  { $inc: { age: 1 } }
)

Push to Array

db.users.updateOne(
  { name: "Charlie" },
  { $push: { hobbies: "swimming" } }
)

Pull from Array

db.users.updateOne(
  { name: "Diana" },
  { $pull: { hobbies: "painting" } }
)

Replace Document

db.users.replaceOne(
  { name: "Bob" },
  { name: "Bobby", age: 31, city: "Berlin", active: true }
)

Upsert (Insert if not exists)

db.users.updateOne(
  { name: "Eve" },
  { $set: { age: 29, city: "Sydney" } },
  { upsert: true }
)

6. DELETE COMMANDS

Delete One

db.users.deleteOne({ name: "Eve" })

Delete Many

db.users.deleteMany({ active: false })

Drop Collection / DB

db.users.drop()
db.dropDatabase()

7. INDEX COMMANDS

// Single field
db.users.createIndex({ age: 1 })

// Compound
db.users.createIndex({ city: 1, age: -1 })

// Unique
db.users.createIndex({ email: 1 }, { unique: true })

// Text index
db.articles.createIndex({ title: "text", content: "text" })

// Partial index
db.users.createIndex(
  { age: 1 },
  { partialFilterExpression: { active: true } }
)

// Sparse
db.users.createIndex({ phone: 1 }, { sparse: true })

// TTL (auto-delete after 1 hour)
db.sessions.createIndex(
  { createdAt: 1 },
  { expireAfterSeconds: 3600 }
)

// List indexes
db.users.getIndexes()

// Drop index
db.users.dropIndex("age_1")

8. AGGREGATION PIPELINE EXAMPLES

Basic: Filter + Project

db.users.aggregate([
  { $match: { age: { $gte: 30 } } },
  { $project: { name: 1, age: 1, _id: 0 } }
])

Group & Count

db.users.aggregate([
  { $group: { _id: "$city", count: { $sum: 1 } } }
])

Average Age per City

db.users.aggregate([
  { $group: {
      _id: "$city",
      avgAge: { $avg: "$age" },
      totalUsers: { $sum: 1 }
  }}
])

Top 2 Cities by User Count

db.users.aggregate([
  { $group: { _id: "$city", count: { $sum: 1 } } },
  { $sort: { count: -1 } },
  { $limit: 2 }
])

Unwind Array

db.users.aggregate([
  { $unwind: "$hobbies" },
  { $group: { _id: "$hobbies", count: { $sum: 1 } } },
  { $sort: { count: -1 } }
])

Lookup (Join)

// Assume orders collection
db.users.aggregate([
  {
    $lookup: {
      from: "orders",
      localField: "name",
      foreignField: "customer",
      as: "orders"
    }
  },
  { $project: { name: 1, orderCount: { $size: "$orders" } } }
])

Add Computed Field

db.users.aggregate([
  {
    $addFields: {
      isAdult: { $gte: ["$age", 18] },
      hobbyCount: { $size: "$hobbies" }
    }
  }
])

Write Output to New Collection

db.users.aggregate([
  { $match: { active: true } },
  { $out: "active_users" }
])

9. SAMPLE DATA FOR PRACTICE

// Insert sample data
db.products.insertMany([
  { name: "Laptop", price: 1200, category: "Electronics", inStock: true, tags: ["portable", "work"] },
  { name: "Mouse", price: 25, category: "Electronics", inStock: true, tags: ["wireless"] },
  { name: "Book", price: 15, category: "Education", inStock: false, tags: ["paperback"] },
  { name: "Pen", price: 2, category: "Stationery", inStock: true, tags: ["blue", "ballpoint"] }
])

db.orders.insertMany([
  { orderId: "O1", customer: "Alice", items: ["Laptop", "Mouse"], total: 1225, status: "shipped" },
  { orderId: "O2", customer: "Bob", items: ["Book"], total: 15, status: "pending" }
])

10. PRACTICE EXERCISES (Try These!)

Find all users older than 28 from Tokyo
js db.users.find({ age: { $gt: 28 }, city: "Tokyo" })
Update all inactive users to active
js db.users.updateMany({ active: false }, { $set: { active: true } })
Count products in "Electronics" category
js db.products.countDocuments({ category: "Electronics" })
Get total sales per customer
js db.orders.aggregate([ { $group: { _id: "$customer", totalSpent: { $sum: "$total" } } } ])
Find products with "wireless" tag
js db.products.find({ tags: "wireless" })
Add index on price and sort descending
js db.products.createIndex({ price: -1 }) db.products.find().sort({ price: -1 })
Create TTL index on createdAt
js db.logs.createIndex({ createdAt: 1 }, { expireAfterSeconds: 86400 })

11. USEFUL SYSTEM COMMANDS

// Server status
db.serverStatus()

// Current operations
db.currentOp()

// Kill long-running op
db.killOp(<opId>)

// Collection stats
db.users.stats()

// Validate collection
db.users.validate()

// Compact (defragment)
db.runCommand({ compact: "users" })

12. MONGOSH TIPS

// Pretty print
.pretty()

// Limit results
.limit(5)

// Count
.count()

// Explain query plan
db.users.find({ age: 30 }).explain("executionStats")

// Clear screen
cls

// Exit
exit

Download This Guide as `.js` File

// Save as: mongodb-practice.js
// Run: mongosh mongodb-practice.js

use practiceDB
db.dropDatabase()

print("=== INSERTING DATA ===")
db.users.insertMany([...])  // paste all insert commands

print("=== PRACTICE QUERIES ===")
// paste all queries

Resources

You now have 100+ working MongoDB commands!
Copy → Paste → Run → Learn

Next Step: Build a mini project (e.g., Todo App, Blog, Inventory) using these commands.

Want a full project template or Node.js + MongoDB example? Just ask!

Last updated: Nov 12, 2025

MongoDB All Commands & Examples for Practice and Learning

MongoDB All Commands & Examples for Practice and Learning

MongoDB All Commands & Examples for Practice and Learning

Setup: Start MongoDB & Connect

1. DATABASE COMMANDS

2. COLLECTION COMMANDS

3. INSERT COMMANDS (CREATE)

Insert One

Insert Many

4. QUERY COMMANDS (READ)

Find All

Find with Condition

Find One

Projection (Select fields)

Logical Operators

Array Queries

Regex

5. UPDATE COMMANDS

Update One

Update Many

Increment / Decrement

Push to Array

Pull from Array

Replace Document

Upsert (Insert if not exists)

6. DELETE COMMANDS

Delete One

Delete Many

Drop Collection / DB

7. INDEX COMMANDS

8. AGGREGATION PIPELINE EXAMPLES

Basic: Filter + Project

Group & Count

Average Age per City

Top 2 Cities by User Count

Unwind Array

Lookup (Join)

Add Computed Field

Write Output to New Collection

9. SAMPLE DATA FOR PRACTICE

10. PRACTICE EXERCISES (Try These!)

11. USEFUL SYSTEM COMMANDS

12. MONGOSH TIPS

Download This Guide as .js File

Resources

MongoDB All Commands & Examples for Practice and Learning

MongoDB All Commands & Examples for Practice and Learning

MongoDB All Commands & Examples for Practice and Learning

Setup: Start MongoDB & Connect

1. DATABASE COMMANDS

2. COLLECTION COMMANDS

3. INSERT COMMANDS (CREATE)

Insert One

Insert Many

4. QUERY COMMANDS (READ)

Find All

Find with Condition

Find One

Projection (Select fields)

Logical Operators

Array Queries

Regex

5. UPDATE COMMANDS

Update One

Update Many

Increment / Decrement

Push to Array

Pull from Array

Replace Document

Upsert (Insert if not exists)

6. DELETE COMMANDS

Delete One

Delete Many

Drop Collection / DB

7. INDEX COMMANDS

8. AGGREGATION PIPELINE EXAMPLES

Basic: Filter + Project

Group & Count

Average Age per City

Top 2 Cities by User Count

Download This Guide as `.js` File

Download This Guide as `.js` File