58、ElasticSearch DSL Bucket、Metric聚合

1. Classification of aggregation

 

2. DSL implements bucket aggregation

# 集合, 1、bucket terms
GET /hotel/_search
{
  "size": 0,
  "aggs": {
    "brandAgg": {
      "terms": {
        "field": "brand",
        "size": 20
      }
    }
  }
} 

3. Bucket aggregation-aggregation structure sorting

 # 集合,2、bucket terms 排序
GET /hotel/_search
{
  "size": 0,
  "aggs": {
    "brandAgg": {
      "terms": {
        "field": "brand",
        "order": {
          "_count": "asc"
        }, 
        "size": 20
      }
    }
  }
}

4. Bucket aggregation - limit the scope of aggregation

 # 集合,3、bucket terms 过滤
GET /hotel/_search
{
  "size": 0,
  "query": {
    "range": {
      "price": {
        "gte": 0,
        "lte": 200
      }
    }
  }, 
  "aggs": {
    "brandAgg": {
      "terms": {
        "field": "brand",
        "size": 20
      }
    }
  }
}

 5. DSL realizes Metrics aggregation

# 聚合，4、metrics 
GET /hotel/_search
{
  "size": 0,
  "aggs": {
    "brandAgg": {
      "terms": {
        "field": "brand",
        "order": {
          "score_stats.max": "asc"
        }, 
        "size": 10
      },
      "aggs": {
        "score_stats": {
          "stats": {
            "field": "score"
          }
        }
      }
    }
  }
} 

6. Summary analysis

This chapter learns what aggregation is and the DSL syntax of Bucket and Metric aggregation

        1. What is aggregation: aggregation is the statistics, analysis, and calculation of documents

        2. Common aggregation: Bucket, Metric, Pipeline

        3. Fields supported by aggregation: keyword, value, date, Boolean

        4. Three elements of aggregation: aggregation name, aggregation type, aggregation field 

The above content comes from dark horse programmers, and the learning rhythm of the course is gradual. I think it is very good after studying, and friends who are interested should not miss it. 

Spring Cloud Dark Horse Programmer Open Course https://www.bilibili.com/video/BV1LQ4y127n4/?spm_id_from=333.337.search-card.all.click&vd_source=14fddb9f4c113af7bdb1f50651dffc4d