$match

Filters documents by a condition.

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Syntax

{ "$match": { <fieldOrOperator>: <valueOrExpression> } }

Use the same field and operator syntax as MongoDB queries ($eq, $gte, logical expressions, nested documents, etc.).

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✅ Basic Example

📌 Stage

{
  "$match": {
    "status": "active"
  }
}

📥 Input

{
  "orderId": 1,
  "status": "active",
  "total": 1200
}

📤 Output

{
  "orderId": 1,
  "status": "active",
  "total": 1200
}

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🧱 Deep Nested Pipeline Usage (Ecommerce)

[
  {
    "$match": {
      "orderDate": {
        "$gte": "2024-01-01"
      }
    }
  },
  {
    "$unwind": "$items"
  },
  {
    "$match": {
      "items.price": {
        "$gt": 100
      }
    }
  }
]

📥 Input Document

{
  "orderId": 2,
  "orderDate": "2025-02-10",
  "items": [
    {
      "name": "Laptop",
      "price": 900
    },
    {
      "name": "Mouse",
      "price": 50
    }
  ]
}

📤 Output Documents

[
  {
    "orderId": 2,
    "orderDate": "2025-02-10",
    "items": {
      "name": "Laptop",
      "price": 900
    }
  }
]

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➕ Supported Accumulators

None for this stage

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🔧 Common Operators

$gte, $lt, $eq, $expr

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