Bagikan melalui

$expr

Operator $expr memungkinkan penggunaan ekspresi agregasi dalam bahasa kueri, yang memungkinkan kami membandingkan bidang dari dokumen yang sama, melakukan perhitungan, dan menggunakan operator agregasi dalam operasi temukan. Operator $expr berguna untuk perbandingan bidang kompleks yang tidak dapat dicapai dengan operator kueri tradisional.

Syntax

{
  $expr: { <aggregation expression> }
}

Parameter-parameternya

Pengaturan Description
<aggregation expression> Ekspresi agregasi valid apa pun yang mengevaluasi ke nilai boolean. Ekspresi mencakup perbandingan bidang, operasi aritmatika, ekspresi kondisional, dan operator agregasi lainnya.

Examples

Pertimbangkan dokumen sampel ini dari koleksi toko.

{
    "_id": "0fcc0bf0-ed18-4ab8-b558-9848e18058f4",
    "name": "First Up Consultants | Beverage Shop - Satterfieldmouth",
    "location": {
        "lat": -89.2384,
        "lon": -46.4012
    },
    "staff": {
        "totalStaff": {
            "fullTime": 8,
            "partTime": 20
        }
    },
    "sales": {
        "totalSales": 75670,
        "salesByCategory": [
            {
                "categoryName": "Wine Accessories",
                "totalSales": 34440
            },
            {
                "categoryName": "Bitters",
                "totalSales": 39496
            },
            {
                "categoryName": "Rum",
                "totalSales": 1734
            }
        ]
    },
    "promotionEvents": [
        {
            "eventName": "Unbeatable Bargain Bash",
            "promotionalDates": {
                "startDate": {
                    "Year": 2024,
                    "Month": 6,
                    "Day": 23
                },
                "endDate": {
                    "Year": 2024,
                    "Month": 7,
                    "Day": 2
                }
            },
            "discounts": [
                {
                    "categoryName": "Whiskey",
                    "discountPercentage": 7
                },
                {
                    "categoryName": "Bitters",
                    "discountPercentage": 15
                },
                {
                    "categoryName": "Brandy",
                    "discountPercentage": 8
                },
                {
                    "categoryName": "Sports Drinks",
                    "discountPercentage": 22
                },
                {
                    "categoryName": "Vodka",
                    "discountPercentage": 19
                }
            ]
        },
        {
            "eventName": "Steal of a Deal Days",
            "promotionalDates": {
                "startDate": {
                    "Year": 2024,
                    "Month": 9,
                    "Day": 21
                },
                "endDate": {
                    "Year": 2024,
                    "Month": 9,
                    "Day": 29
                }
            },
            "discounts": [
                {
                    "categoryName": "Organic Wine",
                    "discountPercentage": 19
                },
                {
                    "categoryName": "White Wine",
                    "discountPercentage": 20
                },
                {
                    "categoryName": "Sparkling Wine",
                    "discountPercentage": 19
                },
                {
                    "categoryName": "Whiskey",
                    "discountPercentage": 17
                },
                {
                    "categoryName": "Vodka",
                    "discountPercentage": 23
                }
            ]
        }
    ]
}

Contoh 1: Membandingkan staf penuh waktu dan paruh waktu

Contoh mengambil toko dengan jumlah karyawan paruh waktu yang lebih besar dari karyawan penuh waktu.

db.stores.find({_id: "40d6f4d7-50cd-4929-9a07-0a7a133c2e74",
  $expr: {
    $gt: ["$staff.employeeCount.partTime", "$staff.employeeCount.fullTime"]
  }
})

Kueri membandingkan dua bidang dalam dokumen (_id) yang ditentukan dan mengembalikannya hanya jika kondisi terpenuhi (jumlah staf penuh waktu melebihi jumlah staf paruh waktu).

{
  "_id": "40d6f4d7-50cd-4929-9a07-0a7a133c2e74",
  "name": "Proseware, Inc. | Home Entertainment Hub - East Linwoodbury",
  "location": {
    "lat": 70.1272,
    "lon": 69.7296
  },
  "staff": {
      "contractorCount": 5,
      "employeeCount": { "fullTime": 19, "partTime": 20 }
    },
  "sales": {
    "totalSales": 151864,
    "salesByCategory": [
      {
        "categoryName": "Sound Bars",
        "totalSales": 2120
      },
      {
        "categoryName": "Home Theater Projectors",
        "totalSales": 45004
      }
    },
    "storeOpeningDate": ISODate("2024-09-23T13:45:01.480Z"),
    "lastUpdated": ISODate("2025-06-11T11:06:57.922Z"),
    "status": "active",
    "category": "high-volume",
    "priority": 1,
    "reviewDate": ISODate("2025-06-11T11:10:50.276Z")
  }
]

Contoh 2: Logika kondisional dengan lokasi penyimpanan

Contoh menunjukkan penggunaan logika kondisional dengan $expr menarik toko di belahan bumi selatan di mana rasio efisiensi staf (penjualan per karyawan) melebihi 2000.

db.stores.find({_id: "40d6f4d7-50cd-4929-9a07-0a7a133c2e74",
  $expr: {
    $and: [
      { $gte: ["$location.lat", 70.1272] },
      {
        $gt: [
          {
            $divide: [
              "$sales.totalSales",
              { $add: ["$staff.employeeCount.fullTime", "$staff.employeeCount.partTime"] }
            ]
          },
          2000
        ]
      }
    ]
  }
}).limit(1)

Kueri ini mengembalikan hasil berikut.

[
  {
    "_id": "40d6f4d7-50cd-4929-9a07-0a7a133c2e74",
    "name": "Proseware, Inc. | Home Entertainment Hub - East Linwoodbury",
    "location": {
      "lat": 70.1272,
      "lon": 69.7296
    },
    "staff": {
      "totalStaff": {
        "fullTime": 19,
        "partTime": 20
      }
    },
    "sales": {
      "totalSales": 151864,
      "salesByCategory": [
        {
          "categoryName": "Sound Bars",
          "totalSales": 2120
        },
        {
          "categoryName": "Home Theater Projectors",
          "totalSales": 45004
        }
      ]
    },
    "storeOpeningDate": ISODate("2024-09-23T13:45:01.480Z"),
    "lastUpdated": ISODate("2025-06-11T11:06:57.922Z"),
    "status": "active",
    "category": "high-volume",
    "priority": 1,
    "reviewDate": ISODate("2025-06-11T11:10:50.276Z")
  }
]

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