小编Jen*_*ose的帖子

{
    "_id" : ObjectId("56bd8e9de517259412a743ab"),
    "user_token" : "mzXhdbCu",
    "sender_details" : {
        "location" : "XYZ",
        "zipcode" : "610208"
    },
    "shipping_address" : {
        "location" : "ABC",
        "zipcode" : "602578
    }
}

我一直在尝试从两个计数每个唯一邮政编码的实例数

$sender_details.zipcode

和

$shipping_address.zipcode

我尝试使用以下代码

db.ac_consignments.aggregate({
    $group: {
        _id: {
            "zipcode":"$sender_details.zipcode", 
            "szipcode":"$shipping_address.zipcode"
        }, 
        count: {"$sum":1}
    }
})

我收到的输出是这个

{
    "result" : [ 
        {
            "_id" : {
                "zipcode" : "610208",
                "szipcode" : "602578"
            },
            "count" : 7
        }, 
        {
            "_id" : {
                "zipcode" : "602578",
                "szipcode" : "678705"
            },
            "count" : 51
        } …