Elasticsearch minBy

Question

elasticsearch中有没有办法从包含最大值的文档中获取字段？ （基本上与scala中的maxBy的工作方式相同）

例如（模拟）：

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.net.ssl.HttpsURLConnection;

import org.apache.commons.io.IOUtils;

public class MobileSample {

    public static void main(String[] args) throws IOException {
        URL url = new URL("https://<mobile_service_name>.azure-mobile.net/api/<api_name: example 'filestorage'>");
        HttpURLConnection https = (HttpURLConnection) url.openConnection();
        https.addRequestProperty("X-ZUMO-APPLICATION", "<manage_access_key>");
        https.connect();
        int respCode = https.getResponseCode();
        System.out.println(respCode);
        InputStream is = https.getInputStream();
        IOUtils.copy(is, new FileOutputStream("<file_name>"));
        is.close();
    }
}

{ "aggregations": { "grouped": { "terms": { "field": "grouping", "order": { "docWithMin": "asc" } }, "aggregations": { "withMax": { "max": { "maxByField": "a", "field": "b" } } } } } } 会返回（类似）：{"grouping":1,"a":2,"b":5},{"grouping":1,"a":1,"b":10}，其中最大值来自第一个对象，因为{"grouped":1,"withMax":5}更高。

Answer 1

假设您只想要回复最多的文档，您可以这样做：

{
  "size": 0,
  "aggs": {
    "grouped": {
      "terms": {
        "field": "grouping"
      },
      "aggs": {
          "maxByA": {
            "top_hits": {
            "sort": [
             {"a": {"order": "desc"}}
            ],
            "size": 1
          }
        }
      }
    }
  }
}