创建多个MongoDB查询的Spring Data Aggregation

Question

The database MongoDB I have stored documents in the format:

    {
      "achievement": [
        {
          "userFromId":"max",
          "userToId":"peter",
          "date":"2016-01-25",
          "pointCount":1,
          "description":"good work",
          "type":"THANKS"
        }
      ]
    }

How to get the number of records in the database (if any) for the a certain date, in which people are thanking the other people. I created a query to retrieve data:

    DBObject clause1 = new BasicDBObject("userFromId", userFromId);
    DBObject clause2 = new BasicDBObject("userToId", userToId);
    DBObject clause3 = new BasicDBObject("sendDate", localDate);
    DBObject clause4 = new BasicDBObject("type", Thanks);
    BasicDBList or = new BasicDBList();
    or.add(clause1);
    or.add(clause2);
    or.add(clause3);
    or.add(clause4);
    DBObject query = new BasicDBObject("$or", or);

But I do not know how to get the number of records and how can rewrite the query using aggregation? For example:

        Aggregation aggregation = Aggregation.newAggregation(
            Aggregation.group("userFromId")
                .first("userFromId").as("userFromId")
                .sum("pointCount").as("pointCount"));

I do not know how to add a few more parameters. What the return request if the data to the database does not exist?

Thanks for any help

Answer 1

You can use something like this. This will count all the number of documents matching the below criteria.

Regular Query

db.collection.count({ $or: [ { "userFromId": userFromId }, { "userToId": userToId } ] });

Using Aggregation

db.collection.aggregate( [
  { $match: { $or: [ { "userFromId": userFromId }, { "userToId": userToId } ] } },
  { $group: { _id: null, count: { $sum: 1 } } }
] );