The Aggregation Pipeline: $match, $group & $project

« Deleting Records & TTL Auto-Expiring Documents« Previous Schema Design: Embedding vs. Referencing »Next »

Process streams of documents through multi-stage aggregation pipelines for reporting, data reshaping, and analytics.

Multi-Stage Document Processing

Documents enter a multi-stage pipeline where each stage transforms the data stream: $match filters rows, $group aggregates sums and averages, and $project reshapes final fields.

3-Stage Aggregation Pipeline

Try It Yourself »

db.orders.aggregate([
  // Stage 1: Filter active orders
  { $match: { status: "completed" } },
  // Stage 2: Group by customer
  { $group: {
      _id: "$customerId",
      totalSpent: { $sum: "$total" },
      itemCount: { $sum: 1 }
  }},
  // Stage 3: Sort by highest spenders
  { $sort: { totalSpent: -1 } }
]);

Google AdSense Slot (inContentBanner)

Set your Publisher ID in src/config/ads.ts to display live ads.

Test Yourself With Exercise

+15 XP

Which aggregation pipeline stage filters documents to allow only those that match specified conditions to proceed to the next stage?

« Previous: Deleting Records & TTL Auto-Expiring Documents Next: Schema Design: Embedding vs. Referencing »