[ElasticSearch] Aggregation :带过滤

SQL场景：带过滤条件的聚合查询

SELECT COUNT(color)  FROM table where price >= 10000 and price < 35000 GROUP BY color

查询在一定价格区间内的销售车辆颜色分布

Aggregation API:
在API实现上是先做过滤再聚合

GET /cars/transactions/_search
{
  "size": 0, 
    "query": {
        "range" : {
            "price" : {
                "gte" : 10000,
                "lt" :  35000
            }
        }
    },
    "aggs" : { 
        "popular_colors" : { 
            "terms" : { 
              "field" : "color"
            }
        }
    }
}

java API：

def aggTest2(): Unit = {
    import scala.collection.JavaConverters._
   // 构造RangeQuery
    val rangeQuery = QueryBuilders.rangeQuery("price").gte(10000).lt(35000)

  // 构造Aggregation
    val agg = AggregationBuilders
      .terms("color")
      .field("color")
      .order(Terms.Order.count(false))

  // 组合&执行查询
    val searchRes = queryBuilder
      .setQuery(rangeQuery)
      .addAggregation(agg)
      .execute()
      .actionGet()
    searchRes.getAggregations.get("color").asInstanceOf[Terms].getBuckets.asScala.foreach{ bucket =>
      println(s"key: ${bucket.getKeyAsString}, value ${bucket.getDocCount}")
    }
  }