mongodb-aggregation-pipeline

name	mongodb-aggregation-pipeline
version	2.1.0
description	Master MongoDB aggregation pipeline for complex data transformations. Learn pipeline stages, grouping, filtering, and data transformation. Use when analyzing data, creating reports, or transforming documents.
sasmp_version	1.3.0
bonded_agent	02-mongodb-queries-aggregation
bond_type	PRIMARY_BOND
capabilities	["pipeline-construction","stage-optimization","data-transformation","analytics-queries","report-generation"]
input_validation	{"required_context":["collection_name","desired_output"],"optional_context":["sample_documents","performance_requirements","index_availability"]}
output_format	{"pipeline":"array","explanation":"string","performance_notes":"array","alternatives":"array"}
error_handling	{"common_errors":[{"code":"AGG001","condition":"Invalid stage syntax","recovery":"Validate stage operators and field references"},{"code":"AGG002","condition":"Memory limit exceeded","recovery":"Add $allowDiskUse: true or optimize with $match early"},{"code":"AGG003","condition":"Unwind on null array","recovery":"Use preserveNullAndEmptyArrays: true"}]}
prerequisites	{"mongodb_version":"4.4+","required_knowledge":["basic-crud","query-operators"],"recommended_indexes":["Fields used in $match stages"]}
testing	{"unit_test_template":"// Test aggregation pipeline\nconst result = await collection.aggregate(pipeline).toArray()\nexpect(result).toHaveLength(expectedCount)\nexpect(result[0]).toMatchObject(expectedShape)\n"}

MongoDB Aggregation Pipeline

Master powerful data transformation with aggregation pipeline.

Quick Start

Basic Pipeline Structure

const result = await collection.aggregate([
  { $match: { status: 'active' } },
  { $group: { _id: '$category', count: { $sum: 1 } } },
  { $sort: { count: -1 } },
  { $limit: 10 }
]).toArray();

Common Pipeline Stages

// $match: Filter documents (like WHERE in SQL)
{ $match: { age: { $gte: 18 }, status: 'active' } }

// $group: Group documents and aggregate
{ $group: {
  _id: '$city',
  total: { $sum: '$amount' },
  average: { $avg: '$price' },
  count: { $sum: 1 }
}}

// $project: Transform fields
{ $project: {
  name: 1,
  email: 1,
  fullName: { $concat: ['$firstName', ' ', '$lastName'] },
  : 
}}


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