按日期排序聚合mongodb

Question

我正在尝试使用聚合按日期对文档进行排序。但我做不到。我的尝试如下。我错过了什么吗？

public static JSONArray get_users_from_db(String botId, String pageId, MongoTemplate mongoTemplate) throws Exception {
        AggregationResults<AgentUserLogs> groupResults = mongoTemplate.aggregate(makeQuery(botId, pageId), "chatuser_log", AgentUserLogs.class);
        List<AgentUserLogs> list = groupResults.getMappedResults();
        JSONArray array = new JSONArray();
        Gson gson = new Gson();
        for (AgentUserLogs obj : list) {
            array.put(new JSONObject(gson.toJson(obj)));
        }
        return array;
    }

 private static Aggregation makeQuery(String botId, String pageId) {
        return newAggregation(
            match(Criteria.where("bot_id").is(botId).and("page_id").is(pageId)),
            group(Fields.fields().and("first_name", "$meta_data.user_data.first_name").and("last_name", "$meta_data.user_data.last_name").and("profile_pic", "$meta_data.user_data.profile_pic").and("user_id", "$user_id").and("last_message", "$live_agent.last_message").and("last_access_time", "$meta_data.last_access_time")),
            sort(Sort.Direction.DESC, "last_access_time")
        );
    }

public class AgentUserLogs {

    private String first_name;
    private String last_name;
    private String profile_pic;
    private String user_id;
    private Instant last_access_time;
    private Object last_message;

    @Override
    public String toString() {
        return "{" +
            "first_name='" + first_name + '\'' +
            "last_name='" + last_name + '\'' +
            "profile_pic='" + profile_pic + '\'' +
            "user_id='" + user_id + '\'' +
            "last_access_time='" + last_access_time + '\'' +
            "last_message='" + last_message + '\'' +
            "}";
    }
}

示例文档

{
    "_id" : ObjectId("5a0698755a640c6324a17581"),
    "bot_id" : "1",
    "page_id" : "2039339889632748",
    "user_id" : "1258922750901107"
    "meta_data" : 
        "user_data" : {
            "first_name" : "Januka",
            "last_name" : "Samaranayake",
            "profile_pic" : "https://scontent.xx.fbcdn.net/v/t1.0-1/23172506_1725189057492533_3460235097206138375_n.jpg?oh=5183e7dd4e8ac49a49491055c24696d6&oe=5AA59955",
        },
    },
    "live_agent" : {
        "last_message" : {
            "time" : "Sun Nov 12 12:24:53 IST 2017",
            "message" : "hh",
            "status" : "notRead"
        },
        "thread" : [ 
            {
                "from" : "user",
                "time" : "Sat Nov 11 15:23:10 IST 2017",
                "message" : {
                    "message" : "Default",
                    "type" : "init"
                }
            }, 
            {
                "from" : "user",
                "time" : "Sun Nov 12 11:08:55 IST 2017",
                "message" : {
                    "message" : "hi",
                    "type" : "text"
                }
            }, 
            {
                "from" : "agent",
                "time" : "Sun Nov 12 11:38:14 IST 2017",
                "message" : {
                    "message" : "hello",
                    "type" : "text"
                }
            }, 
            {
                "from" : "agent",
                "time" : "Sun Nov 12 11:42:31 IST 2017",
                "message" : {
                    "message" : "hi",
                    "type" : "text"
                }
            }, 
            {
                "from" : "agent",
                "time" : "Sun Nov 12 12:23:31 IST 2017",
                "message" : {
                    "message" : "hi",
                    "type" : "text"
                }
            }, 
            {
                "from" : "user",
                "time" : "Sun Nov 12 12:24:53 IST 2017",
                "message" : {
                    "message" : "hh",
                    "type" : "text"
                }
            }
        ],
        "connect" : false,
        "status" : "New"
    } }

Answer 1

我认为你的$group 和$sort 有错误

从您粘贴的示例文档中，我无法确定您的 last_access_time 实际存储在哪里，但从您的模型 (AgentUserLogs) 看来，您已将其与可以在字段 @ 下找到的其余字段一起存储987654324@。 这是您最后一个错误的分组字段：

and("last_access_time", "$meta_data.last_access_time")

我相信你的意思是：

and("last_access_time", "$meta_data.user_data.last_access_time")

然后在您的$sort 中，因为您按它进行分组，这意味着它可以通过_id.last_access_time 访问。因此，您的最后一个排序管道必须如下所示：

sort(Sort.Direction.DESC, "_id.last_access_time")

根据您的代码，您的聚合管道应该如下所示（这只是一个示例）：

db.getCollection('yourCollectionName').aggregate([{
        $match: {
            "bot_id": "1",
            "page_id": "2039339889632748"
        }
    },
    {
        $group: {
            _id: {
                first_name: "$meta_data.user_data.first_name",
                last_name: "$meta_data.user_data.last_name",
                profile_pic: "$meta_data.user_data.profile_pic",
                user_id: "$user_id",
                last_message: "$live_agent.last_message",
                last_access_time: "$meta_data.user_data.last_access_time"
            }
        }

    },

    {
        $sort: {
            "_id.last_access_time": -1
        }
    }
])