在MongoDB 4.2中按天标记N个重置次数最多的文档

Question

我有一个计划的文件集合：

{ _id: ObjectId, userId: ObjectId, marker: string, datetime: Date, etc... }

这是绑定到用户（marker）的标记（userId）的集合。装订日期存储在datetime字段中。

每天用户可以接收任意数量的标记。

[当我从此集合中获取数据时，我需要添加一个名为allowed且类型为boolean的额外字段，并且仅当该记录位于日历的N个最近期记录中时，此字段才必须为true用户的一天。

例如，如果初始集合看起来像这样，并且N == 2：

{_id: ..., userId: "a", marker: "m1", datetime: "2020-01-01.10:00"}
{_id: ..., userId: "a", marker: "m2", datetime: "2020-01-02.10:00"}
{_id: ..., userId: "a", marker: "m3", datetime: "2020-01-02.11:00"}
{_id: ..., userId: "a", marker: "m4", datetime: "2020-01-02.12:00"}
{_id: ..., userId: "a", marker: "m5", datetime: "2020-01-02.13:00"}
{_id: ..., userId: "b", marker: "m1", datetime: "2020-01-01.10:00"}
{_id: ..., userId: "b", marker: "m2", datetime: "2020-01-01.11:00"}
{_id: ..., userId: "b", marker: "m3", datetime: "2020-01-01.13:00"}
{_id: ..., userId: "b", marker: "m4", datetime: "2020-01-02.11:00"}
{_id: ..., userId: "b", marker: "m5", datetime: "2020-01-02.12:00"}
{_id: ..., userId: "b", marker: "m6", datetime: "2020-01-03.10:00"}

然后，最终结果应如下所示：

{_id: ..., userId: "a", marker: "m1", datetime: "2020-01-01.10:00", allowed: true}
{_id: ..., userId: "a", marker: "m2", datetime: "2020-01-02.10:00", allowed: true}
{_id: ..., userId: "a", marker: "m3", datetime: "2020-01-02.11:00", allowed: true}
{_id: ..., userId: "a", marker: "m4", datetime: "2020-01-02.12:00", allowed: false}
{_id: ..., userId: "a", marker: "m5", datetime: "2020-01-02.13:00", allowed: false}
{_id: ..., userId: "b", marker: "m1", datetime: "2020-01-01.10:00", allowed: true}
{_id: ..., userId: "b", marker: "m2", datetime: "2020-01-01.11:00", allowed: true}
{_id: ..., userId: "b", marker: "m3", datetime: "2020-01-01.13:00", allowed: false}
{_id: ..., userId: "b", marker: "m4", datetime: "2020-01-02.11:00", allowed: true}
{_id: ..., userId: "b", marker: "m5", datetime: "2020-01-02.12:00", allowed: true}
{_id: ..., userId: "b", marker: "m6", datetime: "2020-01-03.10:00", allowed: true}

我正在使用MongoDB 4.2。

Answer 1

db.markers.aggregate([{ $addFields: { 'datetime': { $arrayElemAt: [{ $split: ["$datetime", "."] }, 0] } } },
{ $group: { _id: { userId: '$userId', datetime: '$datetime' }, data: { $push: '$$ROOT' } } }, {
    $addFields: {
        data: {
            $map:
            {
                input: "$data",
                as: "each",
                in: { $cond: [{ $lte: [{ $indexOfArray: ["$data", '$$each'] }, 1] }, { $mergeObjects: ['$$each', { allowed: true }] }, { $mergeObjects: ['$$each', { allowed: false }] }] }
            }
        }
    }
}, { $unwind: '$data' }, { $replaceRoot: { newRoot: "$data" } }])