《MongoDB高手课》学习记录（第五天）

第五天

今天学习的是《09 | 实验：聚合查询》章节，主要内容是聚合部分的练习。但其实就讲了一个例子，选梳理了一下语法实现。然后演示了怎么用compass工具来可视化的生成聚合查询。

使用的表

> db.orders.findOne()
{
    "_id" : ObjectId("5dbe7a545368f69de2b4d36e"),
    "street" : "493 Hilll Curve",
    "city" : "Champlinberg",
    "state" : "Texas",
    "country" : "Malaysia",
    "zip" : "24344-1715",
    "phone" : "425.956.7743 x4621",
    "name" : "Destinee Schneider",
    "userId" : 3573,
    "orderDate" : ISODate("2019-03-26T03:20:08.805Z"),
    "status" : "created",
    "shippingFee" : NumberDecimal("8.00"),
    "orderLines" : [
        {
            "product" : "Refined Fresh Tuna",
            "sku" : "2057",
            "qty" : 25,
            "price" : NumberDecimal("56.00"),
            "cost" : NumberDecimal("46.48")
        },
        {
            "product" : "Refined Concrete Ball",
            "sku" : "1738",
            "qty" : 61,
            "price" : NumberDecimal("47.00"),
            "cost" : NumberDecimal("47")
        },
        {
            "product" : "Rustic Granite Towels",
            "sku" : "500",
            "qty" : 62,
            "price" : NumberDecimal("74.00"),
            "cost" : NumberDecimal("62.16")
        },
        {
            "product" : "Refined Rubber Salad",
            "sku" : "1400",
            "qty" : 73,
            "price" : NumberDecimal("93.00"),
            "cost" : NumberDecimal("87.42")
        },
        {
            "product" : "Intelligent Wooden Towels",
            "sku" : "5674",
            "qty" : 72,
            "price" : NumberDecimal("84.00"),
            "cost" : NumberDecimal("68.88")
        },
        {
            "product" : "Refined Steel Bacon",
            "sku" : "5009",
            "qty" : 8,
            "price" : NumberDecimal("53.00"),
            "cost" : NumberDecimal("50.35")
        }
    ],
    "total" : NumberDecimal("407")
}

计算所有订单的总销售额

> db.orders.aggregate([{
$group:
  {
    _id: null,
    total: { $sum: "$total"}
  }
}])
{ "_id" : null, "total" : NumberDecimal("44019609") }
>

查询2019年第一季度(1月1日~3月31日)已完成订单(completed)的订单总金额和订单总数

>db.orders.aggregate(
[{$match: {
  status: "completed",
  orderDate: {
    $gte: ISODate('2019-01-01'),
    $lt: ISODate('2019-04-01')
  }
}}, {$group: {
  _id: null,
  total: {
    $sum: "$total"
  },
  shippingFee: {
    $sum: "$shippingFee"
  },
  count: {
    $sum: 1
  }
}}, {$project: {
  grandTotal: {
    $add: ["$total", "$shippingFee"]
  },
  count: 1,
    _id: 0
}}]
)

{ "count" : 5875, "grandTotal" : NumberDecimal("2636376.00") }

使用 Compass

还是用工具比较舒服