在ElasticSearch中聚合嵌套對象

Question

假設我們有此文檔：

{
    "Article" : [
      {
        "id" : 12
        "title" : "An article title",
        "categories" : [1,3,5,7],
        "tag" : ["elasticsearch", "symfony",'Obtao'],
        "author" : [
            {
                "firstname" : "Francois",
                "surname": "francoisg",
                "id" : 18
            },
            {
                "firstname" : "Gregory",
                "surname" : "gregquat"
                "id" : "2"
            }
        ]
      }
    },
    {
        "id" : 13
        "title" : "A second article title",
        "categories" : [1,7],
        "tag" : ["elasticsearch", "symfony",'Obtao'],
        "author" : [
            {
                "firstname" : "Gregory",
                "surname" : "gregquat",
                "id" : "2"
            }
        ]
      }
}

如何按ID查找所有唯一作者？ 什么是正確的查詢？ 我需要返回所有唯一作者（“ author.id”）

感謝幫助。

Answer 1

首先，您應該為字段author設置nested類型的映射。 第二，正如@Taras_Kohut所述，在重新索引整個數據之后，您可以執行以下操作：

{
  "size": 0,
  "aggregations": {
    "records": {
      "nested": {
        "path": "author"
      },
      "aggregations": {
        "ids": {
          "terms": {
            "field": "author.id"
          }
        }
      }
    }
  }
}

請參閱嵌套聚合