聚合查询: 也就是类似mysql的count，max，avg等查询，但要更为强大
聚合查询语法
POST /index/type/_search
{
"aggs":{
"名字":{
"agg_type":{
"属性":"值"
}
}
}
}
一. 去重计数查询:Cardinality
去掉重复的数据，然后算出总数，也就是
Cardinality; 如查询总共几个省.
java 中的重复计数查询
1 //重复计数查询 2 @Test 3 public void cardinalityQuery() throws IOException { 4 // 1. 创建查询对象 5 String index = "sms-logs-index"; 6 String type = "sms-logs-type"; 7 SearchRequest searchRequest = new SearchRequest(index);//指定索引 8 searchRequest.types(type);//指定类型 9 // 2. 封装查询条件 10 String aggName = "agg"; 11 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); 12 searchSourceBuilder.aggregation(AggregationBuilders.cardinality(aggName).field("province")); 13 searchRequest.source(searchSourceBuilder); 14 15 // 3.执行查询 16 // client执行 17 HttpHost httpHost = new HttpHost("192.168.43.30", 9200); 18 RestClientBuilder restClientBuilder = RestClient.builder(httpHost); 19 RestHighLevelClient restHighLevelClient = new RestHighLevelClient(restClientBuilder); 20 SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); 21 22 // 4.获取数据(source中的数据) 23 Cardinality aggregation = search.getAggregations().get(aggName); //用Cardinality接收 24 System.out.println(aggregation.getValue()); 25 }
二. 范围统计
根据某个属性的范围，统计文档的个数，(from 包含, to不包含)
针对不同的类型指定不同的方法，
数值：range
时间：date_range
ip：ip_range
数值统计:
日期型范围查询(data_range):加一个format来规定格式
ip范围统计(ip_range)
java中用range查询
1 @Test 2 public void rangeQuery() throws IOException { 3 // 1. 创建查询对象 4 String index = "sms-logs-index"; 5 String type = "sms-logs-type"; 6 SearchRequest searchRequest = new SearchRequest(index);//指定索引 7 searchRequest.types(type);//指定类型 8 // 2. 封装查询条件 9 String aggName = "agg"; 10 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); 11 searchSourceBuilder.aggregation(AggregationBuilders.range(aggName).field("fee").addUnboundedTo(3) 12 .addRange(3,4) 13 .addUnboundedFrom(4)); 14 searchRequest.source(searchSourceBuilder); 15 16 // 3.执行查询 17 // client执行 18 HttpHost httpHost = new HttpHost("192.168.43.30", 9200); 19 RestClientBuilder restClientBuilder = RestClient.builder(httpHost); 20 RestHighLevelClient restHighLevelClient = new RestHighLevelClient(restClientBuilder); 21 SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); 22 23 // 4.获取数据(source中的数据) 24 Range range = search.getAggregations().get(aggName);//用Range接收 25 List<? extends Range.Bucket> buckets = range.getBuckets(); 26 for( Range.Bucket bucket : buckets ){ 27 System.out.println(bucket.getDocCount()); 28 29 } 30 31 32 }
3. 统计聚合查询
可以查询属性(
field)的最大值，最小值，平均值，平方和.......
1 @Test 2 public void extended_status_Query() throws IOException { 3 // 1. 创建查询对象 4 String index = "sms-logs-index"; 5 String type = "sms-logs-type"; 6 SearchRequest searchRequest = new SearchRequest(index);//指定索引 7 searchRequest.types(type);//指定类型 8 // 2. 封装查询条件 9 String aggName = "agg"; 10 SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder(); 11 searchSourceBuilder.aggregation(AggregationBuilders.extendedStats(aggName).field("fee")); 12 searchRequest.source(searchSourceBuilder); 13 14 // 3.执行查询 15 // client执行 16 HttpHost httpHost = new HttpHost("192.168.43.30", 9200); 17 RestClientBuilder restClientBuilder = RestClient.builder(httpHost); 18 RestHighLevelClient restHighLevelClient = new RestHighLevelClient(restClientBuilder); 19 SearchResponse search = restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT); 20 21 // 4.获取数据(source中的数据) 22 ExtendedStats aggregation = search.getAggregations().get(aggName);//用Range接收 23 System.out.println(aggregation.getMax()); 24 System.out.println(aggregation.getSum()); 25 System.out.println(aggregation.getAvg()); 26 }
https://www.elastic.co/guide/en/elasticsearch/reference/6.5/getting-started.html