如何使用給定的時間戳在 mongodb 中查找每天的最后一條記錄？

Question

我正在使用 MongoDB 存儲數據，每 15 分鍾一次將一條新記錄插入 DB。所以我想使用給定的時間戳下載報告。 如果我 select 2021 年 1 月 1 日星期五上午 12:00:00（ 1609459200000 ）時間戳到 2021 年 1 月 3 日星期日下午 11:59:59（ 1609718399000 ）時間戳，我應該只得到 3 條記錄作為響應。

db.vehicle.aggregate( [ { "$match": { "time": {"$gte":1609459200000,"$lte":1609718399000 }} }, { "$sort": { "time": 1 } } , { $group: { _id: "$speed", time: { $last: "$time" } } } ]);

I tried the above query but it's giving all the records

謝謝你。

示例數據庫記錄：

// Day 1
{
   "_id":"100",
   "vehical":"train_1",
   "speed":"100kmh",
   "time":1609459200000,
   "starting_point":12
},
{
   "_id":"101",
   "vehical":"train_1",
   "speed":"120kmh",
   "time":1609460100000,
   "starting_point":13
},
{
   "_id":"102",
   "vehical":"train_1",
   "speed":"125kmh",
   "time":1609461000000,
   "starting_point":14
},
// Day 2
{
   "_id":"201",
   "vehical":"train_1",
   "speed":"100kmh",
   "time":1609545600000,
   "starting_point":15
},
{
   "_id":"202",
   "vehical":"train_1",
   "speed":"130kmh",
   "time":1609546500000,
   "starting_point":16
},
// Day 3
{
   "_id":"301",
   "vehical":"train_1",
   "speed":"100kmh",
   "time":1609632000000,
   "starting_point":20
},
{
   "_id":"302",
   "vehical":"train_1",
   "speed":"140kmh",
   "time":1609632900000,
   "starting_point":21
}

回復：

// Day 1
{
   "_id":"102",
   "vehical":"train_1",
   "speed":"125kmh",
   "time":1609461000000,
   "starting_point":14
},
// Day 2
{
   "_id":"202",
   "vehical":"train_1",
   "speed":"130kmh",
   "time":1609546500000,
   "starting_point":16
},
// Day 3
{
   "_id":"302",
   "vehical":"train_1",
   "speed":"140kmh",
   "time":1609632900000,
   "starting_point":21
}

Answer 1

試試這個：

db.vehicle.aggregate([
   { $match: { time: { $gte: 1609459200000, $lte: 1609718399000 } } },
   { $set: { timestamp: { $toDate: "$time" } } },
   { $sort: { time: 1 } },
   {
      $group: {
         _id: {
            $dateFromParts: {
               year: { $year: "$timestamp" },
               month: { $month: "$timestamp" },
               day: { $dayOfMonth: "$timestamp" }
            }
         },
         last: { $last: "$$ROOT" }
      }
   },
   { $replaceRoot: { newRoot: "$last" } }
]);

Answer 2

7個月前有人發布了類似的問題。 這可能會回答您的問題： 如何在 MongoDB 集合中獲取每天的最后一個文檔？

如果這對您不起作用，並且您知道當天的最后一條記錄將始終同時生成，那么您應該能夠使用 $hour 和 $minute 構建查詢。

https://docs.mongodb.com/manual/reference/operator/aggregation/hour/
https://docs.mongodb.com/manual/reference/operator/aggregation/minute/