聚合查询
简介
聚合：英文为Aggregation，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。
注意事项：text类型是不支持聚合的。
测试数据
# 创建索引 index 和映射 mapping
PUT /fruit
{
"mappings": {
"properties": {
"title":{
"type": "keyword"
},
"price":{
"type":"double"
},
"description":{
"type": "text",
"analyzer": "ik_max_word"
}
}
}
}
# 放入测试数据
PUT /fruit/_bulk
{
"index":{
}}
{
"title" : "面包","price" : 19.9,"description" : "小面包非常好吃"}
{
"index":{
}}
{
"title" : "旺仔牛奶","price" : 29.9,"description" : "非常好喝"}
{
"index":{
}}
{
"title" : "日本豆","price" : 19.9,"description" : "日本豆非常好吃"}
{
"index":{
}}
{
"title" : "小馒头","price" : 19.9,"description" : "小馒头非常好吃"}
{
"index":{
}}
{
"title" : "大辣片","price" : 39.9,"description" : "大辣片非常好吃"}
{
"index":{
}}
{
"title" : "透心凉","price" : 9.9,"description" : "透心凉非常好喝"}
{
"index":{
}}
{
"title" : "小浣熊","price" : 19.9,"description" : "童年的味道"}
{
"index":{
}}
{
"title" : "海苔","price" : 19.9,"description" : "海的味道"}
使用
Terms
根据某个字段分组
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# 根据某个字段进行分组 统计数量
GET /fruit/_search
{
"query": {
"term": {
"description": {
"value": "好吃"
}
}
},
"aggs": {
"price_group": {
"terms": {
"field": "price"
}
}
}
}
求最大值
# 求最大值
GET /fruit/_search
{
"aggs": {
"price_max": {
"max": {
"field": "price"
}
}
}
}
求最小值
# 求最小值
GET /fruit/_search
{
"aggs": {
"price_min": {
"min": {
"field": "price"
}
}
}
}
求平均值
# 求平均值
GET /fruit/_search
{
"aggs": {
"price_agv": {
"avg": {
"field": "price"
}
}
}
}
求和
# 求和
GET /fruit/_search
{
"aggs": {
"price_sum": {
"sum": {
"field": "price"
}
}
}
}
整合应用
//求和 平均 最大值 最小值聚合，桶中只有一个返回值
//分组聚合
@Test
public void testAggsFun() throws IOException {
SearchRequest searchRequest = new SearchRequest("fruit");
SearchSourceBuilder sourceBuilder = new SearchSourceBuilder();
sourceBuilder
.query(QueryBuilders.matchAllQuery())
.size(0)
//聚合处理，针对某个字段进行分组
.aggregation(AggregationBuilders.sum("price_sum").field("price"));
// .aggregation(AggregationBuilders.avg("price_avg").field("price")); //平均值
// .aggregation(AggregationBuilders.max("price_min").field("price")); //最小值
// .aggregation(AggregationBuilders.min("price_max").field("price")); //最大值
searchRequest.source(sourceBuilder);
SearchResponse response = elasticsearchClient.search(searchRequest, RequestOptions.DEFAULT);
//处理聚合结果
Aggregations aggregations = response.getAggregations();
ParsedSum parsedSum= aggregations.get("price_sum");
System.out.println(parsedSum.getValue());
}