共用方式為

$or

運算子 $or 會在表達式陣列上執行邏輯 OR 運算，並擷取至少滿足其中一個指定條件的檔。

語法

{
    $or: [{
        < expression1 >
    }, {
        < expression2 >
    }, ..., {
        < expressionN >
    }]
}

參數

參數 Description
expression 表達式的數組，其中至少一個必須為真，文件才能被包含進來。

範例

請參考商店集合中的此範例檔。

{
    "_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
                }
            ]
        }
    ]
}

範例 1：使用 OR 作業作為邏輯查詢

此查詢會擷取擁有超過 15 名全職員工或超過 20 名兼職員工的商店，並在這兩個條件下使用 $or 運算子執行查詢。 然後，只投影結果集中商店的名稱和員工欄位。

db.stores.find(
  {
    $or: [
      { "staff.employeeCount.fullTime": { $gt: 15 } },
      { "staff.employeeCount.partTime": { $gt: 20 } }
    ]
  },
  {
    "name": 1,
    "staff": 1
  }
).limit(2)

此查詢傳回的前兩個結果是：

[
  {
    "_id": "dda2a7d2-6984-40cc-bbea-4cbfbc06d8a3",
    "name": "Contoso, Ltd. | Home Improvement Closet - Jaskolskiview",
    "staff": {
      "employeeCount": {
        "fullTime": 16,
        "partTime": 8
      }
    }
  },
  {
    "_id": "44fdb9b9-df83-4492-8f71-b6ef648aa312",
    "name": "Fourth Coffee | Storage Solution Gallery - Port Camilla",
    "staff": {
      "employeeCount": {
        "fullTime": 17,
        "partTime": 15
      }
    }
  }
]

範例 2：使用 OR 運算子做為布爾運算式來識別具有高銷售額或大型員工的商店

此查詢會擷取總銷售額超過 50,000 人或員工總數超過 25 人的商店。

db.stores.aggregate([
  {
    $project: {
      name: 1,
      totalSales: "$sales.totalSales",
      totalStaff: { 
        $add: ["$staff.employeeCount.fullTime", "$staff.employeeCount.partTime"] 
      },
      qualifiesForProgram: {
        $or: [
          { $gt: ["$sales.totalSales", 50000] },
          { $gt: [{ $add: ["$staff.employeeCount.fullTime", "$staff.employeeCount.partTime"] }, 25] }
        ]
      }
    }
  },
  { $limit: 4 }
])

此查詢傳回的前四個結果為：

[
  {
    "_id": "905d1939-e03a-413e-a9c4-221f74055aac",
    "name": "Trey Research | Home Office Depot - Lake Freeda",
    "totalStaff": 31,
    "qualifiesForProgram": true
  },
  {
    "_id": "a715ab0f-4c6e-4e9d-a812-f2fab11ce0b6",
    "name": "Lakeshore Retail | Holiday Supply Hub - Marvinfort",
    "totalStaff": 27,
    "qualifiesForProgram": true
  },
  {
    "_id": "923d2228-6a28-4856-ac9d-77c39eaf1800",
    "name": "Lakeshore Retail | Home Decor Hub - Franciscoton",
    "totalStaff": 13,
    "qualifiesForProgram": false
  },
  {
    "_id": "7e53ca0f-6e24-4177-966c-fe62a11e9af5",
    "name": "Contoso, Ltd. | Office Supply Deals - South Shana",
    "totalStaff": 2,
    "qualifiesForProgram": false
  }
]

效能考量

  • 檢閱尋找更佳效能的建議。
    • 陣列中的每個 $or 條件都會獨立評估
    • 盡可能使用索引以提升效能
    • 考慮最佳執行的條件順序
    • 針對相同的欄位進行多個相等檢查時，應使用 $in 而不要用 $or。
    • 讓條件數目 $or 保持合理

相關內容

  • Last updated on