我想做一个相当复杂的查询/聚合。我看不到该怎么做，因为我刚刚开始使用ES。我的文档看起来像这样：

{
  "keyword": "some keyword",
  "items": [
    {
      "name":"my first item",
      "item_property_1":"A",
      ( other properties here )
    },
    {
      "name":"my second item",
      "item_property_1":"B",
      ( other properties here )
    },
    {
      "name":"my third item",
      "item_property_1":"A",
      ( other properties here )
    }
  ]
  ( other properties... )
},
{
  "keyword": "different keyword",
  "items": [
    {
      "name":"cool item",
      "item_property_1":"A",
      ( other properties here )
    },
    {
      "name":"awesome item",
      "item_property_1":"C",
      ( other properties here )
    },
  ]
  ( other properties... )
},
( other documents... )

现在，我想为每个关键字计算property_1可以具有的几个可能值中有多少个。也就是说，我需要一个具有以下响应的存储桶聚合：

{
  "keyword": "some keyword",
  "item_property_1_aggretation": [
    {
      "key":"A",
      "count": 2,
    },
    {
      "key":"B",
      "count": 1,
    }
  ]
},
{
  "keyword": "different keyword",
  "item_property_1_aggretation": [
    {
      "key":"A",
      "count": 1,
    },
    {
      "key":"C",
      "count": 1,
    }
  ]
},
( other keywords... )

如果需要映射，您还可以指定哪个吗？我没有任何非默认映射，我只是将所有内容都转储在那里。

编辑：通过在此处发布上一个示例的批量PUT为您节省了麻烦

PUT /test/test/_bulk
{ "index": {}}
{  "keyword": "some keyword",  "items": [    {      "name":"my first item",      "item_property_1":"A"    },    {      "name":"my second item",      "item_property_1":"B"    },    {      "name":"my third item",      "item_property_1":"A"     }  ]}
{ "index": {}}
{  "keyword": "different keyword",  "items": [    {      "name":"cool item",      "item_property_1":"A"    },    {      "name":"awesome item",      "item_property_1":"C"    }  ]}

编辑2：

我只是试过这个：

POST /test/test/_search
{
    "size":2,
    "aggregations": {
        "property_1_count": {
            "terms":{
                "field":"item_property_1"
            }
        }
    }
}

并得到了这个：

"aggregations": {
   "property_1_count": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
         {
            "key": "a",
            "doc_count": 2
         },
         {
            "key": "b",
            "doc_count": 1
         },
         {
            "key": "c",
            "doc_count": 1
         }
      ]
   }
}

关闭但没有雪茄。您可以看到发生了什么，item_property_1无论keyword它们属于哪个，它都在进行存储。我确定该解决方案涉及正确添加一些映射，但是我无法全力以赴。有什么建议吗？

EDIT3：基于此：https ://www.elastic.co/guide/zh-
cn/elasticsearch/reference/current/mapping-nested-type.html
我想尝试将一个nested类型添加到property items。为此，我尝试：

PUT /test/_mapping/test
{
    "test":{
        "properties": {
            "items": {
                "type": "nested",
                "properties": {
                    "item_property_1":{"type":"string"}
                }
            }
        }
    }
}

但是，这将返回错误：

{
   "error": "MergeMappingException[Merge failed with failures {[object mapping [items] can't be changed from non-nested to nested]}]",
   "status": 400
}

这可能与该URL上的警告有关：“将对象类型更改为嵌套类型需要重新索引。”

那么，我该怎么做呢？