Question

我想在当前查询结果上区分name，我怎么能在MongoDB上做

查询语法

db_conn.medical_records.find({"$or": [{"symptom_1": "nose allergic"},{"symptom_2": "nose allergic"}]})

当前查询结果，但不在名称

上应用distinct

{
    "id": 1,
    "name": "Mary",    
    "symptom_1": null,
    "symptom_2": "nose allergic",
    "datetime": "2011-04-02"
},

{
    "id": 2,
    "name": "Jack",
    "symptom_1": "nose allergic",
    "symptoms_2": null,
    "datetime": "2011-04-02"
},

{
    "id": 3,
    "name": "Mark",
    "symptoms_1": null,
    "symptoms_2": "nose allergic",
    "datetime": "2010-01-02"
},

{
    "id": 4,
    "name": "Mark",
    "symptoms_1": "nose allergic",
    "symptoms_2": "headach",
    "datetime": "2015-04-04"
},

根据现有查询

应用不同的运算符

我想在当前查询结果上区分name，我怎么能在MongoDB上做

查询语法

db_conn.medical_records.find({"$or": [{"symptom_1": "nose allergic"},{"symptom_2": "nose allergic"}]})

当前查询结果，但不在名称

上应用distinct

{
    "id": 1,
    "name": "Mary",    
    "symptom_1": null,
    "symptom_2": "nose allergic",
    "datetime": "2011-04-02"
},

{
    "id": 2,
    "name": "Jack",
    "symptom_1": "nose allergic",
    "symptoms_2": null,
    "datetime": "2011-04-02"
},

{
    "id": 3,
    "name": "Jack",
    "symptoms_1": null,
    "symptoms_2": "nose allergic",
    "datetime": "2010-01-02"
},

{
    "id": 4,
    "name": "Mark",
    "symptoms_1": "nose allergic",
    "symptoms_2": "headach",
    "datetime": "2015-04-04"
}

预期结果

["Mary", "Jack", "Mark"]

Answer 1

使用collection.distinct

db_conn.medical_records.distinct("name", 
    {
        "$or": [
                   { "symptom_1": <your symptom> },
                   { "symptom_2": <your symptom> }
               ]
    }
)

Answer 2

您需要先修复密钥名称。如果是＆＃39; sympton_1＆＃39;请修复或者＆＃39; symptons_1＆＃39;然后在您的收藏中应用mongo distinct。在distinct中，您也可以指定条件。

db.collection.distinct({
    "$or": [
                { "symptom_1": "nose allergic" },
                { "symptom_2": "nose allergic" } // here you need to fix key name as it is 'symptoms_1' in some documents
            ]
 }

）

根据现有查询应用distinct运算符

2 个答案: