MongoDB 中按日期与本地时区分组

使用MongoDB进行数据分析和查询是非常常见的任务。在MongoDB中，我们可以使用聚合管道操作来对数据进行分组和聚合。今天，我们将讨论如何根据日期和本地时区对数据进行分组。

javascript
db.userActivity.aggregate([
  {
    $group: {
      _id: {
        date: { $dateToString: { format: "%Y-%m-%d", date: "$timestamp", timezone: "$timezone" } },
        timezone: "$timezone"
      },
      count: { $sum: 1 }
    }
  },
  {
    $sort: {
      "_id.date": 1,
      "_id.timezone": 1
    }
  }
])

javascript
[
  {
    "_id": 1,
    "timestamp": ISODate("2022-01-01T10:00:00Z"),
    "timezone": "Asia/Shanghai"
  },
  {
    "_id": 2,
    "timestamp": ISODate("2022-01-01T12:00:00Z"),
    "timezone": "Asia/Tokyo"
  },
  {
    "_id": 3,
    "timestamp": ISODate("2022-01-02T09:00:00Z"),
    "timezone": "America/New_York"
  },
  {
    "_id": 4,
    "timestamp": ISODate("2022-01-02T10:00:00Z"),
    "timezone": "America/Los_Angeles"
  },
  {
    "_id": 5,
    "timestamp": ISODate("2022-01-02T12:00:00Z"),
    "timezone": "Asia/Shanghai"
  }
]

javascript
[
  {
    "_id": {
      "date": "2022-01-01",
      "timezone": "Asia/Shanghai"
    },
    "count": 1
  },
  {
    "_id": {
      "date": "2022-01-01",
      "timezone": "Asia/Tokyo"
    },
    "count": 1
  },
  {
    "_id": {
      "date": "2022-01-02",
      "timezone": "America/Los_Angeles"
    },
    "count": 1
  },
  {
    "_id": {
      "date": "2022-01-02",
      "timezone": "America/New_York"
    },
    "count": 1
  },
  {
    "_id": {
      "date": "2022-01-02",
      "timezone": "Asia/Shanghai"
    },
    "count": 1
  }
]