按日期在Morphia中进行汇总 [英] Aggregation by date in Morphia

问题描述

我正在尝试将基于PostgreSQL的应用程序迁移到MongoDB。我正在使用Morphia连接到MongoDB。

I'm trying to migrate a PostgreSQL-based application to MongoDB. I'm using Morphia to connect to MongoDB.

在我的应用中，我有以下查询来获取Hibernate的测量列表：

In my app I have this query to get a list of measurements with Hibernate:

...
jpq = jpq.from(qm)
      .where(qm.parameter.eq(parameter));
jpq = jpq.where(qm.dateTime.between(startDate, endDate));
...
case MINUTE: 
    jpq = jpq.groupBy(qm.dateTime.minute());
case HOUR:
    jpq = jpq.groupBy(qm.dateTime.hour());
case DAY:
    jpq = jpq.groupBy(qm.dateTime.dayOfMonth());
case MONTH:
    jpq = jpq.groupBy(qm.dateTime.month());
case YEAR:
    jpq = jpq.groupBy(qm.dateTime.year());
....

我正在尝试在Morphia中创建这样的查询：

I am trying to create a query like this in Morphia:

db.MongoMeasurement.aggregate(
           [
             {
              $group : {
                _id : { month: { $month: "$dateTime" }, day: { $dayOfMonth: "$dateTime" }, year: { $year: "$dateTime" } },
                 averageValue: { $avg: "$value" },
                count: { $sum: 1 }
               }
           }
       ]
   )

..但是我很难找到有关如何在Morphia中编写此查询的文档。

.. but I'm having trouble finding documentation on how to write this query in Morphia.

推荐答案

我没有找到如何在Morphia中编写查询的方法，但是我使用Jongo解决了我的问题

I dont found how write the query in Morphia, but i solve my problem using Jongo

        ....
        DB db = mongo.getDB("BD");
        Jongo jongo = new Jongo(db);
        jongoCo = jongo.getCollection("MongoMeasurement");
        ....
        List<MongoMeasurement> cursor = jongoCo.aggregate("{$group:{"
            + "_id:{ month: { $month: '$dateTime' }, day: { $dayOfMonth: '$dateTime' }, year: { $year: '$dateTime' } },"
            + "value: { $avg: '$value' },"
            + "dateTime:{$min:'$dateTime'},"
            + "count:{$sum:1}"
            + "}}")
            .as(MongoMeasurement.class);

这篇关于按日期在Morphia中进行汇总的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！