准备环境

spring-data-elasticsearch3.2.12.RELEASE

# 订单索引，一个订单下有多个商品
PUT order_test
{
  "mappings": {
    "properties": {
      // 订单状态 0未付款 1未发货 2运输中 3待签收 4已签收 
      "status": {
        "type": "integer"
      },
      // 订单编号
      "no": {
        "type": "keyword"
      },
      // 下单时间
      "create_time": {
        "type": "date",
        "format": "yyyy-MM-dd HH:mm:ss"
      },
      // 订单金额
      "amount": {
        "type": "double"
      },
      // 创建人
      "creator":{
        "type": "keyword"
      },
      // 商品信息
      "product":{
        "type": "nested",
        "properties": {
          // 商品ID
          "id": {
            "type": "keyword"
          },
          // 商品名称
          "name":{
            "type": "keyword"
          },
          // 商品价格
          "price": {
            "type": "double"
          },
          // 商品数量
          "quantity": {
            "type": "integer"
          }
        }
      }
    }
  }
}

测试数据

POST order_test/_bulk
{"index":{}}
{"status":0,"no":"DD202205280001","create_time":"2022-05-01 12:00:00","amount":100.0,"creator":"张三","product":[{"id":"1","name":"苹果","price":20.0,"quantity":5}]}
{"index":{}}
{"status":0,"no":"DD202205280002","create_time":"2022-05-01 12:00:00","amount":100.0,"creator":"李四","product":[{"id":"2","name":"香蕉","price":20.0,"quantity":5}]}
{"index":{}}
{"status":1,"no":"DD202205280003","create_time":"2022-05-02 12:00:00","amount":100.0,"creator":"张三","product":[{"id":"2","name":"香蕉","price":20.0,"quantity":5}]}
{"index":{}}
{"status":2,"no":"DD202205280004","create_time":"2022-05-01 12:00:00","amount":150.0,"creator":"王二","product":[{"id":"1","name":"苹果","price":30.0,"quantity":5}]}
{"index":{}}
{"status":2,"no":"DD202205280005","create_time":"2022-05-03 12:00:00","amount":100.0,"creator":"55555","product":[{"id":"2","name":"香蕉","price":20.0,"quantity":5}]}
{"index":{}}
{"status":3,"no":"DD202205280006","create_time":"2022-05-04 12:00:00","amount":150.0,"creator":"李四","product":[{"id":"3","name":"榴莲","price":150.0,"quantity":1}]}
{"index":{}}
{"status":4,"no":"DD202205280007","create_time":"2022-05-04 12:00:00","amount":100.0,"creator":"张三","product":[{"id":"2","name":"香蕉","price":20.0,"quantity":5}]}
{"index":{}}
{"status":3,"no":"DD202205280008","create_time":"2022-05-01 12:00:00","amount":200.0,"creator":"王二","product":[{"id":"1","name":"苹果","price":40.0,"quantity":5}]}
{"index":{}}
{"status":4,"no":"DD202205280009","create_time":"2022-05-03 12:00:00","amount":100.0,"creator":"55555","product":[{"id":"2","name":"香蕉","price":20.0,"quantity":5}]}

分桶聚合 Bucket aggregations

Terms aggregation

分桶聚合中最常用的就是terms聚合了，它可以按照指定字段将数据分组聚合，类似mysql中的group by

• 案例

要求统计各种状态的单数

• DSL ```java GET order_test/_search { “size”: 0, “aggs”: { “status_bucket”: {

  "terms": {
    "field": "status"
  }
  

  } } }

- java
```java
public void termsAgg(){
    String aggName = "status_bucket";
    NativeSearchQueryBuilder queryBuilder =  new NativeSearchQueryBuilder();
    queryBuilder.withPageable(PageRequest.of(0,1));
    TermsAggregationBuilder termsAgg = AggregationBuilders.terms(aggName).field("status");
    queryBuilder.addAggregation(termsAgg);
    Aggregations aggregations = restTemplate.query(queryBuilder.build(), SearchResponse::getAggregations);
    Terms terms = aggregations.get(aggName);
    List<? extends Terms.Bucket> buckets = terms.getBuckets();
    HashMap<String,Long> statusRes = new HashMap<>();
    buckets.forEach(bucket -> {
        statusRes.put(bucket.getKeyAsString(),bucket.getDocCount());
    });
    System.out.println("---聚合结果---");
    System.out.println(statusRes);
}

Date histogram aggregation

日期分组聚合可以按照日期进行分组，常用到一些日期趋势统计中

• 案例

统计每天的下单量

• DSL ```java GET order_test/_search { “size”: 0, “aggs”: { “date”: {

  "date_histogram": {
    "field": "create_time",
    "calendar_interval": "day",
    "format": "yyyy-MM-dd"
  }
  

  } } }

- java
```java
public void dateHistogramAgg(){
    String aggName = "date";
    DateHistogramAggregationBuilder dateHistogramAggregation = AggregationBuilders.dateHistogram(aggName).field("create_time")
        .calendarInterval(DateHistogramInterval.days(1)).format("yyyy-MM-dd");
    NativeSearchQueryBuilder queryBuilder =  new NativeSearchQueryBuilder();
    queryBuilder.withPageable(PageRequest.of(0,1)).addAggregation(dateHistogramAggregation);
    Aggregations aggregations = restTemplate.query(queryBuilder.build(), SearchResponse::getAggregations);
    ParsedDateHistogram terms = aggregations.get(aggName);
    List<? extends Histogram.Bucket> buckets = terms.getBuckets();
    HashMap<String,Long> resultMap = new HashMap<>();
    buckets.forEach(bucket -> {
        resultMap.put(bucket.getKeyAsString(),bucket.getDocCount());
    });
    System.out.println("---聚合结果---");
    System.out.println(resultMap);
}

拓展：

这里大家会发现使用的是ParsedDateHistogram来承接结果，与上述的Term不一致，那么我们怎么知道什么时候该用哪个呢？实际上可以通过断点来判断
我们通过把断点截取到restTemplate.query的执行结果aggregations之后，会发现该aggregations中的元素已经标明了其类型为ParsedDateHistogram，所以大家只需要跟着用就可以了。

Range aggregation

范围分组聚合可以帮助我们按照指定的数值范围进行分组

• 案例

统计订单金额在0～100，100～200，200+ 这几个区间的订单数量

• DSL ```java GET order_test/_search { “size”: 0, “aggs”: { “date_range”: {

  "range": {
    "field": "amount",
    "ranges": [
      {
        "to": "100"
      },
      {
        "from": "100",
        "to": "200"
      },
      {
        "from": "200"
      }
    ]
  }
  

  } } }

- java
```java
public void rangeAgg(){
    String aggName = "range";
    RangeAggregationBuilder agg = AggregationBuilders.range(aggName).field("amount").addUnboundedTo(100).addRange(100, 200).addUnboundedFrom(200);
    NativeSearchQueryBuilder queryBuilder =  new NativeSearchQueryBuilder();
    queryBuilder.withPageable(PageRequest.of(0,1)).addAggregation(agg);
    Aggregations aggregations = restTemplate.query(queryBuilder.build(), SearchResponse::getAggregations);
    ParsedRange terms = aggregations.get(aggName);
    List<? extends Range.Bucket> buckets = terms.getBuckets();
    HashMap<String,Long> resultMap = new HashMap<>();
    buckets.forEach(bucket -> {
        resultMap.put(bucket.getKeyAsString(),bucket.getDocCount());
    });
    System.out.println("---聚合结果---");
    System.out.println(resultMap);
}

Nested aggregation

nested聚合专用于json型子对象进行聚合，比如上述案例中product是json型数组，如果当我们想通过商品中的属性来聚合统计时就需要用到nested聚合，直接使用product.name来聚合其结果则不会是我们预期的，这主要与es针对数组的存储形式有关。

• 案例

统计每种货物的订单数

• DSL

  GET order_test/_search
  {
  "size": 0,
  "aggs": {
    "product_nested": {
      "nested": {
        "path": "product"
      },
      "aggs": {
        "name_bucket": {
          "terms": {
            "field": "product.name"
          }
        }
      }
    }
  }
  }
  

• java：这里我们涉及到要设置一个嵌套聚合，可以通过subAggregation方法来定义子聚合 ```java public void nestedAgg(){ String aggName = “product_nested”; String termsAggName = “name_bucket”; NestedAggregationBuilder aggregationBuilder = AggregationBuilders.nested(aggName, “product”).subAggregation(AggregationBuilders.terms(termsAggName).field(“product.name”)); NativeSearchQueryBuilder queryBuilder = new NativeSearchQueryBuilder()

    .withPageable(PageRequest.of(0,1))
    .addAggregation(aggregationBuilder);
  

  Aggregations aggregations = restTemplate.query(queryBuilder.build(), SearchResponse::getAggregations); ParsedNested nestedRes = aggregations.get(aggName); Terms terms = nestedRes.getAggregations().get(termsAggName); List<? extends Terms.Bucket> buckets = terms.getBuckets(); HashMap resMap = new HashMap<>(); buckets.forEach(bucket -> {

    resMap.put(bucket.getKeyAsString(),bucket.getDocCount());
  

  }); System.out.println(“—-聚合结果—-“); System.out.println(resMap); }

<a name="jekKa"></a>
# 数值聚合 Metrics aggregations
<a name="JuIYX"></a>
## 3.1 Sum aggregations
求和聚合是常用的聚合之一，经常与分组聚合配合使用，用来统计出各组下的合计

- 案例

求5月1日销售总额

- DSL：这里我们添加了一个query语句，用来限定聚合范围是5.1日的订单
```java
GET order_test/_search
{
  "query": {
    "range": {
      "create_time": {
        "format": "yyyy-MM-dd",
        "from": "2022-05-01",
        "to": "2022-05-01"
      }
    }
  }, 
  "size": 0,
  "aggs": {
    "sum_amount": {
      "sum": {
        "field": "amount"
      }
    }
  }
}

• java ```java public void sumAgg(){

    String aggName = "sumAmount";
    SumAggregationBuilder agg = AggregationBuilders.sum(aggName).field("amount");
    NativeSearchQueryBuilder queryBuilder =  new NativeSearchQueryBuilder()
            .withPageable(PageRequest.of(0,1))
            .withQuery(QueryBuilders.rangeQuery("create_time").format("yyyy-MM-dd").from("2022-05-01").to("2022-05-01"))
            .addAggregation(agg);
    Aggregations aggregations = restTemplate.query(queryBuilder.build(), SearchResponse::getAggregations);
    ParsedSum metric = aggregations.get(aggName);
    double value = metric.getValue();
    System.out.println("---聚合结果---");
    System.out.println(value);
  

  }

<a name="sSn1c"></a>
## Script aggregation
脚本聚合支持我们通过脚本语言来自定义聚合的数值，es中脚本默认的语言为painless。需要注意的是脚本语法非常影响性能，我们一般是尽量避免使用。同时es中还提供了专门的[脚本数值聚合 script metric aggregation](https://www.elastic.co/guide/en/elasticsearch/reference/7.13/search-aggregations-metrics-scripted-metric-aggregation.html)，但因为不太常用，所以我们这里以更加常用的聚合脚本来讲解

- 案例

求所有货物平均单价

- DSL：注意这里不能直接用product.price。因为product是数组，里面可能包含多种货物，所以应该用订单总金额除以所有订单的货物数量
```java
GET order_test/_search
{
  "size": 0,
  "aggs": {
    "total_amount":{
      "sum": {
        "field": "amount"
      }
    },
    "total_quantity":{
      "sum": {
        "script": {
          "source": """
            int total = 0;
            for(int i=0; i<params._source['product'].size(); i++){
              if(params._source['product'][i]['quantity'] != null){
                total += params._source['product'][i]['quantity'];
              }
            }
            return total;
          """
        }
      }
    }
  }
}

可以看到这里，原本sum聚合中是field属性的，改成了script脚本来动态计算属性值，从而实现聚合。同理，script脚本不仅可以使用到sum聚合中，也可以用到其他metric聚合中。
total_amount除以total_quantity即可得到平均价格

• java ```java public void scriptAgg(){ String totalAmountAggName = “total_amount”; String totalQuantityAggName = “total_quantity”; SumAggregationBuilder amountAgg = AggregationBuilders.sum(totalAmountAggName).field(“amount”); SumAggregationBuilder quantityAgg = AggregationBuilders.sum(totalQuantityAggName).script(

    new Script("int total = 0;\n" +
               "            for(int i=0; i<params._source['product'].size(); i++){\n" +
               "              if(params._source['product'][i]['quantity'] != null){\n" +
               "                total += params._source['product'][i]['quantity'];\n" +
               "              }\n" +
               "            }\n" +
               "            return total;"));
  

  NativeSearchQueryBuilder queryBuilder = new NativeSearchQueryBuilder()

    .withPageable(PageRequest.of(0,1))
    .addAggregation(amountAgg).addAggregation(quantityAgg);
  

  Aggregations aggregations = restTemplate.query(queryBuilder.build(), SearchResponse::getAggregations); ParsedSum amountRes = aggregations.get(totalAmountAggName); ParsedSum quantityRes = aggregations.get(totalQuantityAggName); double avgPrice = amountRes.getValue()/quantityRes.getValue(); System.out.println(“—-聚合结果—-“); System.out.println(avgPrice); }

<a name="KkmKi"></a>
# 管道聚合 Pipeline aggregations
首先要理解管道聚合的概念，与其他聚合不同，管道聚合是在其他聚合的结果下进行聚合操作的，所以管道聚合是配合其他聚合来工作的，而不是像其他聚合那样直接操作文档数据。
<a name="hXtSR"></a>
## Bucket script aggregation
分桶脚本聚合用于多分桶聚合的指标进行二次计算，我们通过案例来具体体会他的用法。

- 案例

求每个订单的货物平均单价

- DSL：我们上述求解过所有订单的货物平均单价，这里需要求解每个订单的货物平均单价，那么就需要先对数据按照订单进行分桶
```java
GET order_test/_search
{
  "size": 0,
  "aggs": {
    "order_bucket": {
      "terms": {
        "field": "no"
      },
      "aggs": {
        "total_amount": {
          "sum": {
            "field": "amount"
          }
        },
        "total_quantity": {
          "sum": {
            "script": {
              "source": """
            int total = 0;
            for(int i=0; i<params._source['product'].size(); i++){
              if(params._source['product'][i]['quantity'] != null){
                total += params._source['product'][i]['quantity'];
              }
            }
            return total;
            """
            }
          }
        },
        "avg_price": {
          "bucket_script": {
            "buckets_path": {
              "amount": "total_amount",
              "quantity": "total_quantity"
            },
            "script": "params.amount / params.quantity"
          }
        }
      }
    }
  }
}

• java：需要注意的是管道聚合使用的聚合生成器就不再是AggregationBuilders类，而是PipelineAggregatorBuilders，其余的用法类似 ```java public void bucketScriptAgg(){

    String aggName = "order_bucket";
    String totalAmountAggName = "total_amount";
    String totalQuantityAggName = "total_quantity";
    String avgPriceAggName = "avg_price";
  
    HashMap<String,String> bucketsPath = new HashMap<>();
    bucketsPath.put("amount","total_amount");
    bucketsPath.put("quantity","total_quantity");
    TermsAggregationBuilder aggregationBuilder = AggregationBuilders.terms(aggName).field("no")
            .subAggregation(AggregationBuilders.sum(totalAmountAggName).field("amount"))
            .subAggregation(AggregationBuilders.sum(totalQuantityAggName).script(
                    new Script("int total = 0;\n" +
                            "            for(int i=0; i<params._source['product'].size(); i++){\n" +
                            "              if(params._source['product'][i]['quantity'] != null){\n" +
                            "                total += params._source['product'][i]['quantity'];\n" +
                            "              }\n" +
                            "            }\n" +
                            "            return total;")
            ))
            .subAggregation(PipelineAggregatorBuilders.bucketScript(avgPriceAggName, bucketsPath,
                    new Script("params.amount / params.quantity")));
    NativeSearchQueryBuilder queryBuilder =  new NativeSearchQueryBuilder()
            .withPageable(PageRequest.of(0,1))
            .addAggregation(aggregationBuilder);
    Aggregations aggregations = restTemplate.query(queryBuilder.build(), SearchResponse::getAggregations);
    HashMap<String,Double> resultMap = new HashMap<>();
    Terms terms = aggregations.get(aggName);
    List<? extends Terms.Bucket> buckets = terms.getBuckets();
    buckets.forEach(bucket -> {
        ParsedSimpleValue avgRes = bucket.getAggregations().get(avgPriceAggName);
        resultMap.put(bucket.getKeyAsString(),Double.parseDouble(avgRes.getValueAsString()));
    });
    System.out.println("---聚合结果---");
    System.out.println(resultMap);
  

  }

<a name="GIPZi"></a>
## Bucket sort aggregation
bucket sort可以针对聚合结果实现自定义排序、分页，在桶排序中很常用  [https://blog.csdn.net/qq_24950043/article/details/124535801](https://blog.csdn.net/qq_24950043/article/details/124535801)

- 案例

求订单货物平均单价TOP5的订单

- DSL：上述题目不仅要求我们订单的货物平均单价，还要根据平均单价排序，且分页取前5
```java
GET order_test/_search
{
  "size": 0,
  "aggs": {
    "order_bucket": {
      "terms": {
        "field": "no"
      },
      "aggs": {
        "total_amount": {
          "sum": {
            "field": "amount"
          }
        },
        "total_quantity": {
          "sum": {
            "script": {
              "source": """
            int total = 0;
            for(int i=0; i<params._source['product'].size(); i++){
              if(params._source['product'][i]['quantity'] != null){
                total += params._source['product'][i]['quantity'];
              }
            }
            return total;
            """
            }
          }
        },
        "avg_price": {
          "bucket_script": {
            "buckets_path": {
              "amount": "total_amount",
              "quantity": "total_quantity"
            },
            "script": "params.amount / params.quantity"
          }
        },
        "avg_price_sort": {
          "bucket_sort": {
            "sort": [
              {"avg_price":{"order":"desc"}}
            ],
            "from": 0,
            "size": 5
          }
        }
      }
    }
  }
}

• java：同上使用的聚合生成器就不再是AggregationBuilders类，而是PipelineAggregatorBuilders，其余的用法类似 ```java public void bucketSortAgg(){

    String aggName = "order_bucket";
    String totalAmountAggName = "total_amount";
    String totalQuantityAggName = "total_quantity";
    String avgPriceAggName = "avg_price";
    String bucketSortAggName = "avg_price_sort";
    HashMap<String,String> bucketsPath = new HashMap<>();
    bucketsPath.put("amount","total_amount");
    bucketsPath.put("quantity","total_quantity");
    List<FieldSortBuilder> sortList = new ArrayList<>();
    FieldSortBuilder fieldSortBuilder = new FieldSortBuilder("avg_price").order(SortOrder.DESC);
    sortList.add(fieldSortBuilder);
    TermsAggregationBuilder aggregationBuilder = AggregationBuilders.terms(aggName).field("no")
            .subAggregation(AggregationBuilders.sum(totalAmountAggName).field("amount"))
            .subAggregation(AggregationBuilders.sum(totalQuantityAggName).script(
                    new Script("int total = 0;\n" +
                            "            for(int i=0; i<params._source['product'].size(); i++){\n" +
                            "              if(params._source['product'][i]['quantity'] != null){\n" +
                            "                total += params._source['product'][i]['quantity'];\n" +
                            "              }\n" +
                            "            }\n" +
                            "            return total;")
            ))
            .subAggregation(PipelineAggregatorBuilders.bucketScript(avgPriceAggName, bucketsPath,
                    new Script("params.amount / params.quantity")))
            .subAggregation(PipelineAggregatorBuilders.bucketSort(bucketSortAggName,sortList).from(0).size(5));
    NativeSearchQueryBuilder queryBuilder =  new NativeSearchQueryBuilder()
            .withPageable(PageRequest.of(0,1))
            .addAggregation(aggregationBuilder);
    Aggregations aggregations = restTemplate.query(queryBuilder.build(), SearchResponse::getAggregations);
    // 因为要求按序输出，所以这里使用LinkedHashMap，HashMap不会按照顺序显示
    LinkedHashMap<String,Double> resultMap = new LinkedHashMap<>();
    Terms terms = aggregations.get(aggName);
    List<? extends Terms.Bucket> buckets = terms.getBuckets();
    buckets.forEach(bucket -> {
        ParsedSimpleValue avgRes = bucket.getAggregations().get(avgPriceAggName);
  
        resultMap.put(bucket.getKeyAsString(),Double.parseDouble(avgRes.getValueAsString()));
  
    });
    System.out.println("---聚合结果---");
    System.out.println(resultMap);
  

  }

```

版本对应

需要注意的是并不是所有的DSL都可以在spring-data-elasticsearch中实现，某些操作在kibana中可以执行，但是在spring-data-elasticsearch中就不能执行了，还要注意es版本与spring-data-elasticsearch的版本统一
https://docs.spring.io/spring-data/elasticsearch/docs/current/reference/html/#preface.requirements