查詢Elasticsearch嵌套類型數據，且只返回嵌套數據中命中的元素.md

測試環境

---

• Elasticsearch 6.3
• Kibana 6.3

造點測試數據

---

新建一個index作為測試

以下是一個存儲博客文章及其評論的數據結構，評論(comments)是nested類型：

PUT /es_blog
{
    "mappings": {
        "blogpost": {
            "properties": {
                "title": {
                    "type": "text"
                },
                "summary": {
                    "type": "text"
                },
                "content": {
                    "type": "text"
                },
                "comments": {
                    "type": "nested",
                    "properties": {
                        "name": {
                            "type": "text"
                        },
                        "comment": {
                            "type": "text"
                        },
                        "age": {
                            "type": "short"
                        },
                        "stars": {
                            "type": "short"
                        },
                        "date": {
                            "type": "date"
                        }
                    }
                }
            }
        }
    }
}

寫入一些測試數據

PUT /es_blog/blogpost/1
{
  "title": "無標題",
  "summary": "全棧工程師、JAVA、HTML5",
  "content": "全棧工程師需要掌握：JAVA、HTML5、JavaScript、常用緩存、大數據等等",
  "comments": [
    {
      "name":    "John Smith",
      "comment": "Great article",
      "age":     28,
      "stars":   4,
      "date":    "2014-09-01"
    },
    {
      "name":    "Alice White",
      "comment": "More like this please",
      "age":     31,
      "stars":   5,
      "date":    "2014-10-22"
    }
  ]
}

PUT /es_blog/blogpost/2
{
  "title": "Java后端開發工程師",
  "summary": "JAVA、Oracle、Hibernate、Spring",
  "content": "Java后端開發工程師需要掌握：JAVA、Oracle、Hibernate、Spring、常用緩存等等",
  "comments": [
    {
      "name":    "John Smith",
      "comment": "工程師真牛",
      "age":     28,
      "stars":   4,
      "date":    "2014-09-01"
    },
    {
      "name":    "Alice White",
      "comment": "Java工程師真牛",
      "age":     31,
      "stars":   5,
      "date":    "2014-10-22"
    }
  ]
}

PUT /es_blog/blogpost/3
{
  "title": "大數據工程師",
  "summary": "Hadoop、Hive、Hdfs、JAVA",
  "content": "大數據工程師需要掌握：Hadoop、Hive、Hdfs、JAVA、Spark、流式計算等等",
  "comments": [
    {
      "name":    "John Smith",
      "comment": "大數據工程師真牛",
      "age":     28,
      "stars":   4,
      "date":    "2014-09-01"
    },
    {
      "name":    "Alice White",
      "comment": "我不會啊",
      "age":     31,
      "stars":   5,
      "date":    "2014-10-22"
    }
  ]
}

PUT /es_blog/blogpost/4
{
  "title": "機器學習工程師",
  "summary": "Python、回歸算法、分類算法、神經網絡、數據基礎",
  "content": "機器學習工程師需要掌握：Python、回歸算法、分類算法、神經網絡、有扎實的數據基礎等等",
  "comments": [
    {
      "name":    "John Smith",
      "comment": "機器學習NX",
      "age":     28,
      "stars":   4,
      "date":    "2014-09-01"
    },
    {
      "name":    "Alice White",
      "comment": "Python好學么？",
      "age":     31,
      "stars":   5,
      "date":    "2014-10-22"
    }
  ]
}

執行查詢

---

查詢文本字段中出現了[工程師]的數據

GET es_blog/blogpost/_search
{
  "_source": {
    "includes": [
      "*"
    ],
    "excludes": [
      "comments"   //去掉返回結果中父級中的comments信息
    ]
  },
  "query": {
    "bool": {
      "should": [
        {
          "match": {
            "title": "工程師"
          }
        },
        {
          "match": {
            "summary": "工程師"
          }
        },
        {
          "match": {
            "content": "工程師"
          }
        },
        {
          "nested": {
            "path": "comments",
            "query": {
              "bool": {
                "should": [
                  {
                    "match": {
                      "comments.comment": "工程師"
                    }
                  }
                ]
              }
            },
            "inner_hits": {}
          }
        }
      ]
    }
  }
}

返回結果：

{
  "took": 9,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 4,
    "max_score": 3.5560012,
    "hits": [
      {
        "_index": "es_blog",
        "_type": "blogpost",
        "_id": "3",
        "_score": 3.5560012,
        "_source": {
          "summary": "Hadoop、Hive、Hdfs、JAVA",
          "title": "大數據工程師",
          "content": "大數據工程師需要掌握：Hadoop、Hive、Hdfs、JAVA、Spark、流式計算等等"
        },
        "inner_hits": {
          "comments": {
            "hits": {
              "total": 1,
              "max_score": 1.8299085,
              "hits": [
                {
                  "_index": "es_blog",
                  "_type": "blogpost",
                  "_id": "3",
                  "_nested": {
                    "field": "comments",
                    "offset": 0
                  },
                  "_score": 1.8299085,
                  "_source": {
                    "name": "John Smith",
                    "comment": "大數據工程師真牛",
                    "age": 28,
                    "stars": 4,
                    "date": "2014-09-01"
                  }
                }
              ]
            }
          }
        }
      },
      {
        "_index": "es_blog",
        "_type": "blogpost",
        "_id": "2",
        "_score": 3.1327708,
        "_source": {
          "summary": "JAVA、Oracle、Hibernate、Spring",
          "title": "Java后端開發工程師",
          "content": "Java后端開發工程師需要掌握：JAVA、Oracle、Hibernate、Spring、常用緩存等等"
        },
        "inner_hits": {
          "comments": {
            "hits": {
              "total": 2,
              "max_score": 2.0794415,
              "hits": [
                {
                  "_index": "es_blog",
                  "_type": "blogpost",
                  "_id": "2",
                  "_nested": {
                    "field": "comments",
                    "offset": 0
                  },
                  "_score": 2.0794415,
                  "_source": {
                    "name": "John Smith",
                    "comment": "工程師真牛",
                    "age": 28,
                    "stars": 4,
                    "date": "2014-09-01"
                  }
                },
                {
                  "_index": "es_blog",
                  "_type": "blogpost",
                  "_id": "2",
                  "_nested": {
                    "field": "comments",
                    "offset": 1
                  },
                  "_score": 1.9221728,
                  "_source": {
                    "name": "Alice White",
                    "comment": "Java工程師真牛",
                    "age": 31,
                    "stars": 5,
                    "date": "2014-10-22"
                  }
                }
              ]
            }
          }
        }
      },
      {
        "_index": "es_blog",
        "_type": "blogpost",
        "_id": "1",
        "_score": 1.7260926,
        "_source": {
          "summary": "全棧工程師、JAVA、HTML5",
          "title": "無標題",
          "content": "全棧工程師需要掌握：JAVA、HTML5、JavaScript、常用緩存、大數據等等"
        },
        "inner_hits": {
          "comments": {
            "hits": {
              "total": 0,
              "max_score": null,
              "hits": []
            }
          }
        }
      },
      {
        "_index": "es_blog",
        "_type": "blogpost",
        "_id": "4",
        "_score": 1.0651813,
        "_source": {
          "summary": "Python、回歸算法、分類算法、神經網絡、數據基礎",
          "title": "機器學習工程師",
          "content": "機器學習工程師需要掌握：Python、回歸算法、分類算法、神經網絡、有扎實的數據基礎等等"
        },
        "inner_hits": {
          "comments": {
            "hits": {
              "total": 0,
              "max_score": null,
              "hits": []
            }
          }
        }
      }
    ]
  }
}

查詢content中出現[java]或評論中出現[python]的數據

GET es_blog/blogpost/_search
{
  "_source": {
    "includes": [
      "*"
    ],
    "excludes": [
      "comments"
    ]
  },
  "query": {
    "bool": {
      "should": [
        {
          "match": {
            "content": "java"
          }
        },
        {
          "nested": {
            "path": "comments",
            "query": {
              "bool": {
                "should": [
                  {
                    "match": {
                      "comments.comment": "python"
                    }
                  }
                ]
              }
            },
            "inner_hits": {}
          }
        }
      ]
    }
  }
}

返回結果

{
  "took": 9,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": 4,
    "max_score": 1.3112576,
    "hits": [
      {
        "_index": "es_blog",
        "_type": "blogpost",
        "_id": "4",
        "_score": 1.3112576,
        "_source": {
          "summary": "Python、回歸算法、分類算法、神經網絡、數據基礎",
          "title": "機器學習工程師",
          "content": "機器學習工程師需要掌握：Python、回歸算法、分類算法、神經網絡、有扎實的數據基礎等等"
        },
        "inner_hits": {
          "comments": {
            "hits": {
              "total": 1,
              "max_score": 1.3112576,
              "hits": [
                {
                  "_index": "es_blog",
                  "_type": "blogpost",
                  "_id": "4",
                  "_nested": {
                    "field": "comments",
                    "offset": 1
                  },
                  "_score": 1.3112576,
                  "_source": {
                    "name": "Alice White",
                    "comment": "Python好學么？",
                    "age": 31,
                    "stars": 5,
                    "date": "2014-10-22"
                  }
                }
              ]
            }
          }
        }
      },
      {
        "_index": "es_blog",
        "_type": "blogpost",
        "_id": "2",
        "_score": 0.75974846,
        "_source": {
          "summary": "JAVA、Oracle、Hibernate、Spring",
          "title": "Java后端開發工程師",
          "content": "Java后端開發工程師需要掌握：JAVA、Oracle、Hibernate、Spring、常用緩存等等"
        },
        "inner_hits": {
          "comments": {
            "hits": {
              "total": 0,
              "max_score": null,
              "hits": []
            }
          }
        }
      },
      {
        "_index": "es_blog",
        "_type": "blogpost",
        "_id": "1",
        "_score": 0.2876821,
        "_source": {
          "summary": "全棧工程師、JAVA、HTML5",
          "title": "無標題",
          "content": "全棧工程師需要掌握：JAVA、HTML5、JavaScript、常用緩存、大數據等等"
        },
        "inner_hits": {
          "comments": {
            "hits": {
              "total": 0,
              "max_score": null,
              "hits": []
            }
          }
        }
      },
      {
        "_index": "es_blog",
        "_type": "blogpost",
        "_id": "3",
        "_score": 0.2876821,
        "_source": {
          "summary": "Hadoop、Hive、Hdfs、JAVA",
          "title": "大數據工程師",
          "content": "大數據工程師需要掌握：Hadoop、Hive、Hdfs、JAVA、Spark、流式計算等等"
        },
        "inner_hits": {
          "comments": {
            "hits": {
              "total": 0,
              "max_score": null,
              "hits": []
            }
          }
        }
      }
    ]
  }
}