ElasticSearch（十）【聚合查询】

约定不等于承诺〃 2024-04-06 10:35 84阅读 0赞

### 十、聚合查询 ###

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上一篇文章《[ElasticSearch - SpringBoot整合][ElasticSearch - SpringBoot]》

> 简介

**聚合**：**英文为Aggregation Aggs，是ES除搜索功能外提供的针对ES数据做统计分析的功能**。聚合有助于根据搜索查询提供聚合数据。聚合查询是数据库中重要的功能特性，ES作为搜索引擎兼数据库，同样提供了强大的聚合分析能力。它基于查询条件来对数据进行分桶、计算的方法。有点类似于SQL中的group by再加一些函数方法的操作

【**注意**】text类型是不支持聚合的

#### 10.1 Kibana操作聚合查询 ####

下面使用size省略查询结果的输出

> terms基于某个字段分组

# 非组名字可以自定义price_group
    GET /products/_search
    {
        
      "query": {
        
        "match_all": {
        }
      },
      "size": 0, 
      "aggs": {
        
        "price_group": {
              
          "terms": {
        
            "field": "price"
          }
        }
      }
    }

![在这里插入图片描述][453dffe2b81e415f802835ef9f6fc23c.png_pic_center]

> 最大值、最小值

# 最大值
    GET /products/_search
    {
        
      "query": {
        
        "match_all": {
        }
      },
      "size": 0, 
      "aggs": {
        
        "max_price": {
              
          "max": {
        
            "field": "price"
          }
        }
      }
    }
    
    # 最小值
    GET /products/_search
    {
        
      "query": {
        
        "match_all": {
        }
      },
      "size": 0, 
      "aggs": {
        
        "min_price": {
              
          "min": {
        
            "field": "price"
          }
        }
      }
    }

![在这里插入图片描述][991805662ed0496f9d38ec9e245dcf12.png_pic_center]

![在这里插入图片描述][34ccae833da847178d8921f3568b3e5c.png_pic_center]

> sum求和、avg平均值

# 求和
    GET /products/_search
    {
        
      "query": {
        
        "match_all": {
        }
      },
      "size": 0, 
      "aggs": {
        
        "sum_price": {
              
          "sum": {
        
            "field": "price"
          }
        }
      }
    }
    
    # 平均值
    GET /products/_search
    {
        
      "query": {
        
        "match_all": {
        }
      },
      "size": 0, 
      "aggs": {
        
        "avg_price": {
              
          "avg": {
        
            "field": "price"
          }
        }
      }
    }

![在这里插入图片描述][2f49082ec6e149e9897231df76df3fa9.png_pic_center]

![在这里插入图片描述][29a99a21f55b44d2837cbfa749ffa3b7.png_pic_center]

#### 10.2 RestHighLevelClient 操作聚合查询 ####

package com.vinjcent;
    
    import org.elasticsearch.action.search.SearchRequest;
    import org.elasticsearch.action.search.SearchResponse;
    import org.elasticsearch.client.RequestOptions;
    import org.elasticsearch.client.RestHighLevelClient;
    import org.elasticsearch.index.query.QueryBuilders;
    import org.elasticsearch.search.aggregations.AggregationBuilders;
    import org.elasticsearch.search.aggregations.Aggregations;
    import org.elasticsearch.search.aggregations.bucket.terms.ParsedDoubleTerms;
    import org.elasticsearch.search.aggregations.bucket.terms.Terms;
    import org.elasticsearch.search.aggregations.metrics.ParsedSum;
    import org.elasticsearch.search.builder.SearchSourceBuilder;
    import org.junit.jupiter.api.Test;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Qualifier;
    import org.springframework.boot.test.context.SpringBootTest;
    
    import java.io.IOException;
    import java.util.List;
    
    @SpringBootTest
    public class RestHighLevelClientAggregationTests {
        
    
        private final RestHighLevelClient restHighLevelClient;
    
        @Autowired
        public RestHighLevelClientAggregationTests(@Qualifier("elasticsearchClient") RestHighLevelClient restHighLevelClient) {
        
            this.restHighLevelClient = restHighLevelClient;
        }
    
    
    
        /**
         * 基于 term 类型进行聚合,并且基于字段进行分组聚合
         * @throws IOException
         */
        @Test
        public void testAggs() throws IOException {
        
    
            // 1.创建请求对象
            SearchRequest searchRequest = new SearchRequest("products");
            // 2.创建查询对象
            SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
            searchSourceBuilder
                    .query(QueryBuilders.matchAllQuery())
                    .aggregation(AggregationBuilders.terms("price_group").field("price"))   // 用于设置聚合处理
                    .size(0);
            // 3.为请求对象配置查询对象
            searchRequest.source(searchSourceBuilder);
            // 4.接收响应对象
            SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
            // 5.处理聚合结果
            Aggregations aggregations = searchResponse.getAggregations();
            // 根据字段类型,转移
            ParsedDoubleTerms price_group = aggregations.get("price_group");
            // 解析桶里的内容
            List<? extends Terms.Bucket> buckets = price_group.getBuckets();
            for (Terms.Bucket bucket : buckets) {
        
                System.out.println(bucket.getKey() + "  " + bucket.getDocCount());
            }
        }
    
    
        /**
         * 基于 sum(ParsedSum)、avg(ParsedAvg)、max(ParsedMax)、min(ParsedMin) 函数聚合,
         * @throws IOException
         */
        @Test
        public void testAggsFunction() throws IOException {
        
            // 1.创建请求对象
            SearchRequest searchRequest = new SearchRequest("products");
            // 2.创建查询对象
            SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
            searchSourceBuilder
                    .query(QueryBuilders.matchAllQuery())
                    .aggregation(AggregationBuilders.sum("sum_price").field("price"))   // 用于设置聚合处理,sum、avg、max、min
                    .size(0);
            // 3.为请求对象配置查询对象
            searchRequest.source(searchSourceBuilder);
            // 4.接收响应对象
            SearchResponse searchResponse = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
            // 5.处理聚合结果
            Aggregations aggregations = searchResponse.getAggregations();
            // 根据字段类型,转移    ParsedSum、ParsedAvg、ParsedMax、ParsedMin
            ParsedSum sum_price = aggregations.get("sum_price");
            // 解析桶里的内容
            System.out.println(sum_price.getValue());
        }
        
    }

下一篇文章《[ElasticSearch - 集群搭建][ElasticSearch -]》

[ElasticSearch - SpringBoot]: https://blog.csdn.net/Wei_Naijia/article/details/126923817
[453dffe2b81e415f802835ef9f6fc23c.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/06/ce95e4072b11471891721886643dff8b.png
[991805662ed0496f9d38ec9e245dcf12.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/06/cb5cb1a315104ce7b4665da090d3d1c8.png
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[2f49082ec6e149e9897231df76df3fa9.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/06/8b742abf111f4b57bfa1b29e056dcba6.png
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[ElasticSearch -]: https://blog.csdn.net/Wei_Naijia/article/details/126923916