mongodb - 基于 ISO 日期值的 Mongo 聚合 $filter

Question

我有以下文件

{
  "_id": "57b4c5f0291ebb13110b888e",
  "first": "John",
  "last": "Smith",
  "email": "John.Smith@gmail.com",
  "fulfillments": [
    {
      "_id": "57b683e531a5a21679b78e6d",
      "created_by_name": "John Smith",
      "created_by_id": "57b4c5f0291ebb23110b888e",
      "fulfilled_by_name": "John Smith",
      "fulfilled_by_id": "57b4c5f0291ebb13110b888e",
      "date": new Date("2016-08-23T13:58:15-0700")
    }
  ]
}

为此，我有一个 mongo 查询，我只想返回尚未发生的履行列表。这意味着date履行嵌入文档上的属性大于当前时间。

db.users.aggregate([
    { $match : { "_id" : "57b4c5f0291ebb13110b888e" } },
    { $project : {
            "fulfillments" : {
                $filter : {
                    "input" : "$fulfillments",
                    "as" : "item",
                    "cond" : ...SOMETHING HERE TO FILTER ON 'date'
                }
            }
        }
    },
    { $unwind : "$fulfillments" },
    { $project : {
            "created_by_name" : "$fulfillments.created_by_name",
            "created_by_id" : "$fulfillments.created_by_id",
            "fulfilled_by_name" : "$fulfillments.fulfilled_by_name",
            "fulfilled_by_id" : "$fulfillments.fulfilled_by_id",
            "date" : "$fulfillments.date"
        }
    }
])

我无法弄清楚仅过滤date尚未发生的履行的正确方法是什么。

Answer 1

以下应该会给你想要的结果

...
$project : {
    "fulfillments" : {
        $filter : {
            "input" : "$fulfillments",
            "as" : "item",
            "cond" : { $gt: [ "$$item.date", new Date() ] }
        }
    }
}
...