es - elasticsearch - aggs - bucket - date

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：date_histogram有什么特点？
答：

问：date_histogram如何使用？
答：

# 删除
DELETE /date_histogram_test

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

# 索引
POST /date_histogram_test/_bulk?routing=1&refresh
{"index": {"_id": 1}}
{"date": "2021-09-29"}
{"index": {"_id": 2}}
{"date": "2021-09-28"}
{"index": {"_id": 3}}
{"date": "2021-09-27"}
{"index": {"_id": 4}}
{"date": "2021-09-30"}
{"index": {"_id": 5}}
{"date": null}


# 搜索 - missing要与format的格式一致
GET /date_histogram_test/_search
{
  "size": 0,
  "aggs": {
    "date_aggs": {
      "date_histogram": {
        "field": "date",
        "calendar_interval": "day",
        "format": "yyyy-MM-dd",
        "keyed": true,
        "missing": "2021-09-30",
        "order": {"_key": "desc"},
        "time_zone": "+08:00"
      }
    }
  }
}

# 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" : {
        "2021-09-30" : {
          "key_as_string" : "2021-09-30",
          "key" : 1632931200000,
          "doc_count" : 2
        },
        "2021-09-29" : {
          "key_as_string" : "2021-09-29",
          "key" : 1632844800000,
          "doc_count" : 1
        },
        "2021-09-28" : {
          "key_as_string" : "2021-09-28",
          "key" : 1632758400000,
          "doc_count" : 1
        },
        "2021-09-27" : {
          "key_as_string" : "2021-09-27",
          "key" : 1632672000000,
          "doc_count" : 1
        }
      }
    }
  }
}


# 搜索 - missing要与format的格式一致
GET /date_histogram_test/_search
{
  "size": 0,
  "aggs": {
    "date_aggs": {
      "date_histogram": {
        "field": "date",
        "fixed_interval": "2d",
        "format": "yyyy-MM-dd",
        "keyed": true,
        "missing": "2021-09-30",
        "order": {"_count": "desc"},
        "offset": "+1d"
      }
    }
  }
}

# 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" : {
        "2021-09-29" : {
          "key_as_string" : "2021-09-29",
          "key" : 1632873600000,
          "doc_count" : 3
        },
        "2021-09-27" : {
          "key_as_string" : "2021-09-27",
          "key" : 1632700800000,
          "doc_count" : 2
        }
      }
    }
  }
}