es - elasticsearch - aggs - bucket - auto

世界上并没有完美的程序，但是我们并不因此而沮丧，因为写程序就是一个不断追求完美的过程。

问：auto_date_histogram有什么特点？
答:

问：auto_date_histogram如何使用？
答：

# 删除
DELETE /auto_date_histogram_test

# 映射
PUT /auto_date_histogram_test
{
  "mappings": {
    "properties": {
      "date": {"type": "date"}
    }
  }
}

# 索引
POST /auto_date_histogram_test/_bulk?refresh
{"index": {"_id": 1}}
{"date": "2021-09-27"}
{"index": {"_id": 2}}
{"date": "2021-08-27"}
{"index": {"_id": 3}}
{"date": "2021-07-23"}
{"index": {"_id": 4}}
{"date": "2021-05-19"}
{"index": {"_id": 5}}
{"date": null}

# 搜索
GET /auto_date_histogram_test/_search
{
  "size": 0,
  "aggs": {
    "date_aggs": {
      "auto_date_histogram": {
        "field": "date",
        "buckets": 10,
        "format": "yyyy-MM-dd",
        "missing": "2021-09-08"
      }
    }
  }
}

# 结果
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 5,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "date_aggs" : {
      "buckets" : [
        {
          "key_as_string" : "2021-05-01",
          "key" : 1619827200000,
          "doc_count" : 1
        },
        {
          "key_as_string" : "2021-06-01",
          "key" : 1622505600000,
          "doc_count" : 0
        },
        {
          "key_as_string" : "2021-07-01",
          "key" : 1625097600000,
          "doc_count" : 1
        },
        {
          "key_as_string" : "2021-08-01",
          "key" : 1627776000000,
          "doc_count" : 1
        },
        {
          "key_as_string" : "2021-09-01",
          "key" : 1630454400000,
          "doc_count" : 2
        }
      ],
      "interval" : "1M"
    }
  }
}