文章/答案/技术大牛

发布

问返回mongodb中的数组
EN

Stack Overflow用户

提问于 2015-02-14 07:20:47

回答 1查看 62关注 0票数 3

我试图在下面的文档中返回数组的某些元素。

{
"_id": 2,
"awardAmount": 6000,
"url": "www.url.com",
"numAwards": 3,
"award": "Faculty Seed Research Grant",
"Type": "faculty",
"Applicates": [
    {
        "School": "psu",
        "Name": "tom",
        "URL": "www.url.com",
        "Time": "",
        "Research": "",
        "Budge": 7500,
        "appId": 100,
        "citizenship": "us",
        "Major": "mat",
        "preAwards": "None",
        "Advisor": ""
    },
    {
        "School": "ffff",
        "Name": "KEVIN",
        "URL": "www.url.com",
        "Time": "5/5/5-6/6/6",
        "Research": "topology",
        "Budge": 9850,
        "appId": 101,
        "citizenship": "us",
        "Major": "gym",
        "preAwards": "None",
        "Advisor": "Dr. cool",
        "Evaluators": [
            {
                "abstractScore": 3,
                "goalsObjectivesScore": 4,
                "evalNum": 1
            },
            {
                "abstractScore": 545646,
                "goalsObjectivesScore": 46546,
                "evalNum": 2
            }
        ]
    }
]
}

我只想要“应用程序”数据，如果他们有一个“评估”字段。以下是我所尝试的

db.coll.find({'Applicates.Evaluators':{'$exists': True }})

这给了我整个文档，但我只想要"Applicates“数据，其中包含”评估器“字段，如下所示。

{
"_id": 2,
"awardAmount": 6000,
"url": "www.url.com",
"numAwards": 3,
"award": "Faculty Seed Research Grant",
"Type": "faculty",
"Applicates": [
    {
        "School": "ffff",
        "Name": "KEVIN",
        "URL": "www.url.com",
        "Time": "5/5/5-6/6/6",
        "Research": "topology",
        "Budge": 9850,
        "appId": 101,
        "citizenship": "us",
        "Major": "gym",
        "preAwards": "None",
        "Advisor": "Dr. cool",
        "Evaluators": [
            {
                "abstractScore": 3,
                "goalsObjectivesScore": 4,
                "evalNum": 1
            },
            {
                "abstractScore": 545646,
                "goalsObjectivesScore": 46546,
                "evalNum": 2
            }
        ]
    }
]
}

python

mongodb

pymongo

aggregation-framework

回答 1

Stack Overflow用户

回答已采纳

发布于 2015-02-14 07:59:22

试试这个(键是使用$unwind操作符)

db.coll.aggregate(
[
{ $match : {'Applicates.Evaluators':{'$exists': true }} },
{ $unwind : "$Applicates" },
{ $match : {'Applicates.Evaluators':{'$exists': true }} },
{ $group : { _id : "$_id", 
    'Applicates' : {$push : '$Applicates'} , 
    awardAmount : {$first : '$awardAmount'},
    url : {$first : '$url'},
    award : {$first : '$award'},
    numAwards : {$first : '$numAwards'},
    award : {$first : '$award'},
    Type : {$first : '$Type'},
    }},
])

票数 3

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/28513445

复制

相似问题

问返回mongodb中的数组
EN

回答 1

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问返回mongodb中的数组EN

回答 1

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问返回mongodb中的数组
EN