找出用户在 MongoDB 上定期活跃的连续天数？

Question

我想找到最后一个用户id的最大连续天数。

   userId(string)           active_date(string) Note: Today (2022-02-20)
------------------------------------------  
{ "userId": "DbdBve", "day": "2022-02-20" }
{ "userId": "DbdBve", "day": "2022-02-19" }
{ "userId": "DbdBve", "day": "2022-02-18" }
{ "userId": "DbdBve", "day": "2022-02-17" } <- Gap here | so user's been active for the last 3 days
{ "userId": "DbdBve", "day": "2022-02-15" }


userId(string)           active_date(string)
------------------------------------------  
{ "userId": "Gj6WEth", "day": "2022-02-20" }
{ "userId": "Gj6WEth", "day": "2022-02-15" } <- Gap here | so user's been active for the last 1 days
{ "userId": "Gj6WEth", "day": "2022-02-14" }
{ "userId": "Gj6WEth", "day": "2022-02-13" }

Answer 1

使用 mongodb v5:

首先使用$toLong

将日期转换为数值

然后使用 $setWindowFields 提取用户 active_days 范围

mongoplayground

db.collection.aggregate([
  {
    "$addFields": {
      "active_date": {
        "$toLong": "$active_date"
      }
    }
  },
  {
    $setWindowFields: {
      partitionBy: "$user_id",
      sortBy: {
        active_date: 1
      },
      output: {
        days: {
          $push: "$active_date",
          window: {
            range: [
              -86400000, // one day in millisecond
              0
            ]
          }
        }
      }
    }
  },
  {
    "$set": {
      "days": {
        "$cond": [
          {
            "$gt": [
              {
                "$size": "$days"
              },
              1
            ]
          },
          0,
          1
        ]
      }
    }
  },
  {
    $setWindowFields: {
      partitionBy: "$user_id",
      sortBy: {
        active_date: 1
      },
      output: {
        count: {
          $sum: "$days",
          window: {
            documents: [
              "unbounded",
              "current"
            ]
          }
        }
      }
    }
  },
  {
    "$group": {
      "_id": {
        user_id: "$user_id",
        count: "$count"
      },
      "active_days": {
        $sum: 1
      },
      "to": {
        "$max": "$active_date"
      },
      "from": {
        "$min": "$active_date"
      }
    }
  }
])

最后通过添加以下两个阶段得到最新的 active_day 范围：

{
  "$sort": {
    to: -1
  }
},
{
  "$group": {
    "_id": "$_id.user_id",
    "last_active_days": {
      "$first": "$active_days"
    }
  }
}

旧版本的 mongodb 使用 $reduce

mongoplayground

db.collection.aggregate([
  {
    $sort: {
      active_date: 1
    }
  },
  {
    "$group": {
      _id: "$user_id",
      dates: {
        "$push": {
          "$toLong": "$active_date"
        },
        
      },
      from: {
        $first: {
          "$toLong": "$active_date"
        }
      },
      to: {
        $last: {
          "$toLong": "$active_date"
        }
      }
    }
  },
  {
    $project: {
      active_days: {
        $let: {
          vars: {
            result: {
              $reduce: {
                input: "$dates",
                initialValue: {
                  prev: {
                    $subtract: [
                      "$from",
                      86400000
                    ]
                  },
                  range: {
                    from: "$from",
                    to: 0,
                    count: 0
                  },
                  ranges: []
                },
                in: {
                  $cond: [
                    {
                      $eq: [
                        {
                          $subtract: [
                            "$$this",
                            "$$value.prev"
                          ]
                        },
                        86400000
                      ]
                    },
                    {
                      prev: "$$this",
                      range: {
                        from: "$$value.range.from",
                        to: "$$value.range.to",
                        count: {
                          $add: [
                            "$$value.range.count",
                            1
                          ]
                        }
                      },
                      ranges: "$$value.ranges"
                    },
                    {
                      ranges: {
                        $concatArrays: [
                          "$$value.ranges",
                          [
                            {
                              from: "$$value.range.from",
                              to: "$$value.prev",
                              count: "$$value.range.count"
                            }
                          ]
                        ]
                      },
                      range: {
                        from: "$$this",
                        to: "$to",
                        count: 1
                      },
                      prev: "$$this"
                    },
                    
                  ]
                }
              }
            }
          },
          in: {
            $concatArrays: [
              "$$result.ranges",
              [
                "$$result.range"
              ]
            ]
          }
        }
      }
    }
  },
  {
    "$project": {
      active_days: {
        "$last": "$active_days.count"
      }
    }
  }
])

找出用户在 MongoDB 上定期活跃的连续天数？

Find the number of consecutive days that users are regularly active on MongoDB?

mongoose

mongodb

node.js

aggregation-framework