Node.js 比较2个嵌入文档的特定字段后获取筛选的文档

我构建了一个列车时刻表集合，我想给出我的函数出发站和到达站，然后函数应该返回符合条件的列车

这是我收藏的一份文件

{
  "_id": 1,
  "train_id": 1,
  "train_type": "VIP",
  "stations": [
    1,
    2,
    3
  ],
  "times": [
    {
      "station_id": 1,
      "order": 1,
      "time": "05:00",
      "days": [
        "sun",
        "mon",
        "wed"
      ]
    },
    {
      "station_id": 2,
      "order": 2,
      "time": "07:00",
      "days": [
        "sun",
        "mon",
        "thu",
        "wed"
      ]
    },
    {
      "station_id": 3,
      "order": 3,
      "time": "08:00",
      "days": [
        "sun",
        "mon",
        "thu"
      ]
    }
  ]
}

所以我想让列车通过1号站和3号站，1号站的顺序应该比3号站的顺序低

---

使用普通的查找或聚合框架？

您可以使用聚合框架来实现这一点。和将完成以下任务：

db.collection.aggregate([
{
    $match : {"stations" : {$all : [1, 3]}} // This to make sure that the contains all the arrival and departure stations 
},
{
    "$addFields" : { // With this you'll get 2 new fields if the "$times" array contains them
        "departureObject" : { $arrayElemAt: [ "$times", { $indexOfArray: [ "$times.station_id", 1 ] } ]},
        "arrivalObject" : { $arrayElemAt: [ "$times", { $indexOfArray: [ "$times.station_id", 3 ] } ]}

    }
},
{
    $match: {$expr: {$gt: ["$arrivalObject.order", "$departureObject.order"]}} // This is to ensure that the arrival station is after departure station 
}
]);

使用示例进行签出