Querying and Filtering

const col = db.collection('products');

// Comparison operators
const expensive = await col.find({ price: { $gt: 100 } }).toArray();
const midRange = await col.find({ price: { $gte: 50, $lte: 200 } }).toArray();
const electronics = await col.find({ category: { $in: ['Electronics', 'Computers'] } }).toArray();
const notElectronics = await col.find({ category: { $nin: ['Electronics'] } }).toArray();

// Logical operators
const premiumApple = await col.find({
  $and: [{ brand: 'Apple' }, { price: { $gt: 500 } }]
}).toArray();

const cheapOrOld = await col.find({
  $or: [{ price: { $lt: 10 } }, { createdAt: { $lt: new Date('2020-01-01') } }]
}).toArray();

// Element operators
const withDiscount = await col.find({ discount: { $exists: true } }).toArray();

// Array operators
const taggedSale = await col.find({ tags: { $all: ['sale', 'featured'] } }).toArray();

// elemMatch - match array elements with multiple conditions
const reviews = await col.find({
  reviews: { $elemMatch: { rating: { $gte: 4 }, verified: true } }
}).toArray();

// Dot notation for nested documents
const parisUsers = await db.collection('users').find({
  'address.city': 'Paris'
}).toArray();

// Regex search
const appleProducts = await col.find({
  name: { $regex: /apple/i }
}).toArray();

// Pagination
const page = 2, pageSize = 10;
const results = await col.find({})
  .sort({ createdAt: -1 })
  .skip((page - 1) * pageSize)
  .limit(pageSize)
  .toArray();