mongodb - 过滤集合但按内部属性排序

Question

考虑到我有如下的文档集合，我想获取如下返回的信息:

从 campaignID = 12 的事件中选择所有条目，按 entries.questionscorrect 降序排序，限制为 10。

我已经对一些查询进行了尝试，但我似乎陷入了这样一个事实，即我在一个级别上进行选择，但想在较低级别(即属性)上订购。

这是我目前所拥有的:

db.getCollection('main').find({"id":4}, {"entries": 1}).sort({"questionscorrect": -1}).limit(2)

请问我如何用 Go (Mgo) 语法或直接的 MongoDB 查询来编写它？

我不断收到返回的信息，但按数量排序

{
    "_id": ObjectId("57f4a590a4be269aa54a0505"),
    "campaignID": 12,
    "name": "name-here",
    "description": "description-here",
    "entries": [{
        "id": 1,
        "nickname": "conorh",
        "name": "conor h***",
        "email": "ch@gmail.com",
        "agreeTerms": true,
        "optInMarketing": false,
        "questionscnswered": 10,
        "questionscorrect": 3
    }, {
        "id": 2,
        "nickname": "bobs",
        "name": "bob smyth",
        "email": "bs12121@gmail.com",
        "agreeTerms": true,
        "optInMarketing": false,
        "questionscnswered": 10,
        "questionscorrect": 6
    }, {
        "id": 3,
        "nickname": "jd12",
        "name": "jane doe",
        "email": "janedough@gmail.com",
        "agreeTerms": true,
        "optInMarketing": false,
        "questionscnswered": 10,
        "questionscorrect": 1
    }]
}

Answer 1

尝试以下:

db.getCollection('main').aggregate([
{$match: {"campaignID" : 12.0}},
{$unwind:"$entries"},
{$sort: {"entries.questionscorrect": -1}},
{$group:{_id:"$_id", 
    "entries":{$push:"$entries"}}}
])