inner hits:

    curl -X PUT "localhost:9200/test" -H 'Content-Type: application/json' -d'
    {
    "mappings": {
        "_doc": {
        "properties": {
            "comments": {
            "type": "nested"
            }
        }
        }
    }
    }
    '
    curl -X PUT "localhost:9200/test/_doc/1?refresh" -H 'Content-Type: application/json' -d'
    {
    "title": "Test title",
    "comments": [
        {
        "author": "kimchy",
        "number": 1
        },
        {
        "author": "nik9000",
        "number": 2
        }
    ]
    }
    '
 

• inner hit 查詢匹配在nested中描述。

  curl -X POST "localhost:9200/test/_search" -H 'Content-Type: application/json' -d'
  {
  "query": {
      "nested": {
      "path": "comments",
      "query": {
          "match": {"comments.number" : 2}
      },
      "inner_hits": {} 
      }
  }
  }
  '
  

• Nested inner hits and _source:在nested欄位裡面查詢_source可能消耗很多時間，特別是size大於預設值的狀況下，可以通過設定_source:false,查詢fields欄位的值減少這種消耗

  curl -X PUT "localhost:9200/test" -H 'Content-Type: application/json' -d'
  {
  "mappings": {
   "_doc": {
      "properties": {
          "comments": {
    "type": "nested"
          }
      }
      }
  }
  }
  '
  curl -X PUT "localhost:9200/test/_doc/1?refresh" -H 'Content-Type: application/json' -d'
  {
  "title": "Test title",
  "comments": [
      {
      "author": "kimchy",
      "text": "comment text"
      },
      {
      "author": "nik9000",
      "text": "words words words"
      }
  ]
  }
  '
  curl -X POST "localhost:9200/test/_search" -H 'Content-Type: application/json' -d'
  {
  "query": {
      "nested": {
      "path": "comments",
      "query": {
          "match": {"comments.text" : "words"}
      },
      "inner_hits": {
          "_source" : false,
          "docvalue_fields" : ["comments.text.keyword"]
      }
      }
  }
  }
  '
   
  

• Hierarchical levels of nested object fields and inner hits.(巢狀裡面包含巢狀的狀況）

  curl -X PUT "localhost:9200/test" -H 'Content-Type: application/json' -d'
  {
  "mappings": {
      "_doc": {
      "properties": {
          "comments": {
          "type": "nested",
          "properties": {
              "votes": {
              "type": "nested"
              }
          }
          }
      }
      }
  }
  }
  '
  curl -X PUT "localhost:9200/test/_doc/1?refresh" -H 'Content-Type: application/json' -d'
  {
  "title": "Test title",
  "comments": [
      {
      "author": "kimchy",
      "text": "comment text",
      "votes": []
      },
      {
      "author": "nik9000",
      "text": "words words words",
      "votes": [
          {"value": 1 , "voter": "kimchy"},
          {"value": -1, "voter": "other"}
      ]
      }
  ]
  }
  '
  curl -X POST "localhost:9200/test/_search" -H 'Content-Type: application/json' -d'
  {
  "query": {
      "nested": {
      "path": "comments.votes",
          "query": {
          "match": {
              "comments.votes.voter": "kimchy"
          }
          },
          "inner_hits" : {
              "_source":false,
              "docvalue_field":["comments.votes.voter.keyword"]}
      }
  }
  }
  '
  

• Parent/child inner hits(通過路由機制實現父子關係）

  curl -X PUT "localhost:9200/test" -H 'Content-Type: application/json' -d'
  {
  "mappings": {
      "_doc": {
      "properties": {
          "my_join_field": {
          "type": "join",
          "relations": {
              "my_parent": "my_child"
          }
          }
      }
      }
  }
  }
  '
  curl -X PUT "localhost:9200/test/_doc/1?refresh" -H 'Content-Type: application/json' -d'
  {
  "number": 1,
  "my_join_field": "my_parent"
  }
  '
  curl -X PUT "localhost:9200/test/_doc/2?routing=1&refresh" -H 'Content-Type: application/json' -d'
  {
  "number": 1,
  "my_join_field": {
      "name": "my_child",
      "parent": "1"
  }
  }
  '
  curl -X POST "localhost:9200/test/_search" -H 'Content-Type: application/json' -d'
  {
  "query": {
      "has_child": {
      "type": "my_child",
      "query": {
          "match": {
          "number": 1
          }
      },
      "inner_hits": {}    
      }
  }
  }
  '