$match & $group Stages

Filtering and Grouping

💡 $match, EK, "FILTER" hai, aur, $group, EK, "CATEGORIZER" hai — $match, se, RELEVANT, DOCUMENTS, CHHAANTE, HO, PHIR, $group, se, UNHE, CATEGORIES, mein, ORGANIZE, karके, SUMMARY, STATISTICS, NIKALТE, HO.

$match, find() ki, TARAH, hi, KAAM, karta hai — QUERY, CONDITION, ke, MATCHING, DOCUMENTS, ko, AGE, STAGE, tak, PASS, karta hai. PIPELINE, ke, SHURU, mein, $match, USE, karna, PERFORMANCE, ke, liye, BEST, hai (jitna, JALDI, DATA, KAM, ho, utna, better).

$group, EK, "_id" FIELD, ke, HISAAB, SE, DOCUMENTS, ko, GROUP, karta hai — $sum, $avg, $max, $min, JAISE, ACCUMULATORS, SE, HAR, GROUP, ke, liye, STATISTICS, CALCULATE, kiye, ja, sakte, HAIN.

db.sales.aggregate([
  { $match: { year: 2024 } },   // sirf 2024 ke sales
  { $group: {
      _id: "$category",          // category ke, hisaab, se, group
      totalRevenue: { $sum: "$amount" },
      avgOrderValue: { $avg: "$amount" },
      orderCount: { $sum: 1 }
  }}
]);

🗃️

$match, EK, "FILTER" hai, aur, $group, EK, "CATEGORIZER" hai — $match, se, RELEVANT, DOCUMENTS, CHHAANTE, HO, PHIR, $group, se, UNHE, CATEGORIES, mein, ORGANIZE, karके, SUMMARY, STATISTICS, NIKALТE, HO.

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⚡ झट से Recap

$match = filter (find() jaisa) — PIPELINE, ke, shuru, mein, use, karo
$group = _id field, ke, hisaab, se, documents, group, karta hai
$sum, $avg, $max, $min = accumulators, HAR, group, ke, liye, statistics

इस page में (2 subtopics)

$group, mein, _id: null, use, karne, se, POORE, dataset, PAR, EK, SINGLE, aggregate, result, milta, hai (grouping, ke, BAJAYE) — jaise, SAARE, orders, ka, TOTAL, revenue, ek, hi, number, mein.

db.orders.aggregate([
  { $group: { _id: null, totalRevenue: { $sum: "$amount" } } }
]);

_id, EK, OBJECT, ho, sakta hai, MULTIPLE, fields, ke, saath — jaise, MONTH, aur, category, ke, hisaab, se, group, karna, EK, hi, time, PAR.

💡Tip: _id: { month: "$month", category: "$category" } se, DONO, fields, ki, UNIQUE, combinations, ke, hisaab, se, groups, bante, hain.

← पिछला🧮 Aggregation Pipeline अगला →🔗 $lookup — Joins in MongoDB

Code10x

$match & $group Stages

_id: null for Overall Aggregation

Grouping by Multiple Fields