Question

我想从我的阵列中的病人那里检索信息，但是在MongoDB网站上找不到这样做的命令。有人可以告诉我正确的检索数据的命令，例如，我想找回病人的名字吗？

{
    "_id" : ObjectId("57113238bde91693e9ff69e7"),
    "docname" : "Arthur Hovsepyan",
    "job_desc" : "Hepatologist",
    "sex" : "male",
    "jobtype" : "fulltime",
    "office" : "room 448",
    "email" : "arturchik@hotmail.com",
    "phone_number" : 862124343,
    "address" : "68 Peterburg street,waterford",
    "hours" : 12,
    "patients" : [
        {
            "name" : "Jenny Power",
            "ward_no" : 1,
            "sex" : "female",
            "termdays" : 2,
            "illness_type" : "minor",
            "age" : 22,
            "phone_number" : 877285221,
            "address" : "63 Johnston street ,Waterford"
        },
        {
            "name" : "Marie Peters",
            "ward_no" : 2,
            "sex" : "female",
            "termdays" : 0,
            "illness_type" : "minor",
            "age" : 21,
            "phone_number" : 862145992,
            "address" : "99 Grange,Waterford"
        },
        {
            "name" : "Philip John",
            "ward_no" : 2,
            "sex" : "male",
            "termdays" : 10,
            "illness_type" : "serious",
            "age" : 31,
            "phone_number" : 861125981,
            "address" : "12 Monvoy Bridge,Waterford"
        },
        {
            "name" : "Marta Peters",
            "ward_no" : 3,
            "sex" : "female",
            "termd7ays" : 0,
            "illness_type" : "minor",
            "age" : 31,
            "phone_number" : 862125981,
            "address" : "100 Grange Manor,Waterford"
        }
    ]
}

Answer 1

可以使用.aggregate()方法和$map运算符完成此操作。

db.collection.aggregate([ 
    { "$project": { 
        "patients": { 
            "$map": { "input": "$patients", "as": "p", "in": "$$p.name" } 
        } 
    }}
])

返回：

{ 
    "_id" : ObjectId("57113238bde91693e9ff69e7"), 
    "patients" : [ "Jenny Power", "Marie Peters", "Philip John", "Marta Peters" ] 
}

您还可以使用.distinct从集合中获取所有名称。

db.collection.distinct("patients.name")

返回：

[ "Jenny Power", "Marie Peters", "Marta Peters", "Philip John" ]

我想检索有关我阵列中患者的信息

1 个答案: