在mongo中返回多个值

Question

我的“accounts”集合中有这些文档

{
        "name" : "Customer-1",
        "lines" : [
                {
                        "type" : "BroadBand",
                        "id" : "<MAC-ADDRESS-1>",
                        "status" : "ON"
                },
                {
                        "type" : "handset",
                        "id" : "<MSISDN-1>",
                        "status" : "ON"
                },
                {
                        "type" : "handset",
                        "id" : "34666468709",
                        "status" : "OFF"
                },
                {
                        "type" : "BroadBand",
                        "id" : "<MAC-ADDRESS-2>",
                        "status" : "OFF"
                }
        ]
}

我尝试了查询：

db.accounts.find({$and: [ {"name":"Customer-1"}]},{"_id":0,"lines":{$elemMatch: {"type":"BroadBand"}}}).pretty()

但它只给了我第一个入口，而不是全部。因此，我希望我的输出仅为具有各自元素的boradband类型，如下所示：

                        "type" : "BroadBand",
                        "id" : "<MAC-ADDRESS-1>",
                        "status" : "ON"

                        "type" : "BroadBand",
                        "id" : "<MAC-ADDRESS-2>",
                        "status" : "OFF"

Answer 1

您可以使用db.collection.aggregate()方法来实现此目的。下面是查询：

db.collection.aggregate([{
"$match": {
  "name": "Customer-1"
}},{
"$unwind": {
  "path": "$lines"
}},{
"$match": {
  "lines.type": "BroadBand"
}}, {
"$group": {
  "_id": "$name",
  "lines": {
    "$push": "$lines"
  }
}},{
"$project": {
  "name": "$_id",
  "lines": 1
}}])