Elasticsearch — 聚合查询，先分组后排序 ，分页

需求
对明细数据先按 waybillId 分组，再按 eventTime 降序，取最新一条数据。

桶聚合（bucket）
Elasticsearch 桶聚合，目的就是数据分组，先将数据按指定的条件分成多个组，然后对每一个组进行统计。

1. ES SQL 写法

    {
      "query": {
        "bool": {
          "must": [
            {
              "match_all": {}
            }
          ]
        }
      },
      "aggs": {
        "waybillIdAgg": {
          "terms": {
            "field": "waybillId",
            "size": 1000,
            "min_doc_count": 1
          },
          "aggs": {
            "top1": {
              "top_hits": {
                "size": 1,
                "sort": [
                  {
                    "eventTime": {
                      "order": "desc"
                    }
                  }
                ]
              }
            }
          }
        }
      }
    }
   

2. Java Elasticsearch 写法及结果解析

    // 查询条件
    BoolQueryBuilder queryBool = QueryBuilders.boolQuery();
   
    BoolQueryBuilder inFilter = new BoolQueryBuilder();
    waybillIds.forEach(
        waybillId -> inFilter.should(QueryBuilders.termQuery("waybillId", waybillId)));
    queryBool.must(inFilter);
   
    // 桶聚合(bucket),按waybillId分组
    TermsAggregationBuilder termsAggregationBuilder =
        AggregationBuilders.terms("waybillIdAgg").field("waybillId").size(1000).minDocCount(1);
    // 嵌套桶，再按时间倒序取第一条数据
    TopHitsAggregationBuilder sort =
        AggregationBuilders.topHits("top1").size(1).sort("eventTime", SortOrder.DESC);
    termsAggregationBuilder.subAggregation(sort);
    // 分页
        SearchSourceBuilder searchSourceBuilder =
            SearchSourceBuilder.searchSource().query(queryBool).aggregation(termsAggregationBuilder)
         	.from(pageIndex <= 1 ? 0 : ((pageIndex - 1) * pageSize)).size(pageSize);
        // 查询请求
    SearchRequest searchRequest = new SearchRequest(esIndexConfig.getIndexNameTrackingDetail());
    searchRequest.source(searchSourceBuilder);
   
    // 执行查询
    SearchResponse searchResponse =
        restHighLevelClient.search(searchRequest, RequestOptions.DEFAULT);
        
    // 处理聚合查询结果
    Aggregations aggregations = searchResponse.getAggregations();
    Terms terms = aggregations.get("waybillIdAgg");
    List trackingDetails =
        terms.getBuckets().stream()
            .map(
                t -> {
                  Aggregation top1 = t.getAggregations().get("top1");
                  Optional first =
                      Arrays.stream(((ParsedTopHits) top1).getHits().getHits()).findFirst();
                  if (first.isPresent()) {
                    Map trackingDetailMap = first.get().getSourceAsMap();
                    return BeanUtil.fillBeanWithMap(trackingDetailMap, new TrackingDetail(), false);
                  }
                  return null;
                })
            .collect(Collectors.toList());