Bucket Aggregation 桶聚合 ---------group by （下）

Reverse Nested Aggregation 反轉嵌套聚合

一種特殊的單桶聚合，支持在嵌套文檔中  聚合父文檔。這種聚合可以有效地 跳出 嵌套塊結構，並鏈接到 其他嵌套結構 或根文檔，從而允許 將不屬於嵌套對象 的其他聚合 嵌套在 嵌套聚合中。
The reverse_nested aggregation 必須被定義在 inside a nested aggregation.

AggregationBuilder aggregation =
    AggregationBuilders
        .nested("agg", "resellers")
        .subAggregation(
                AggregationBuilders
                        .terms("name").field("resellers.name")
                        .subAggregation(
                                AggregationBuilders
                                        .reverseNested("reseller_to_product")
                        )
        );

// sr is here your SearchResponse object
Nested agg = sr.getAggregations().get("agg");
Terms name = agg.getAggregations().get("name");
for (Terms.Bucket bucket : name.getBuckets()) {
    ReverseNested resellerToProduct = bucket.getAggregations().get("reseller_to_product");
    resellerToProduct.getDocCount(); // Doc count
}

Children Aggregation 孩子子聚合

AggregationBuilder aggregation =
    AggregationBuilders
        .children("agg", "reseller"); 

Terms Aggregation 術語聚合

AggregationBuilders
    .terms("genders")
    .field("gender");

ORDER 排序

1.按桶的doc_count升序排序

AggregationBuilders
    .terms("genders")
    .field("gender")
    .order(BucketOrder.count(true))

2.按桶的英文字母順序，按升序排列:

AggregationBuilders
    .terms("genders")
    .field("gender")
    .order(BucketOrder.key(true))

3.按單值  度量子聚合  (由聚合名稱標識)對桶進行排序:

AggregationBuilders
    .terms("genders")
    .field("gender")
    .order(BucketOrder.aggregation("avg_height", false))
    .subAggregation(
        AggregationBuilders.avg("avg_height").field("height")
    )

4.按多個標準排序桶:

AggregationBuilders
    .terms("genders")
    .field("gender")
    .order(BucketOrder.compound( // in order of priority:
        BucketOrder.aggregation("avg_height", false), // sort by sub-aggregation first
        BucketOrder.count(true))) // then bucket count as a tie-breaker
    .subAggregation(
        AggregationBuilders.avg("avg_height").field("height")
    )

Significant Terms Aggregation  重要術語聚合

AggregationBuilder aggregation =
        AggregationBuilders
                .significantTerms("significant_countries")
                .field("address.country");

// Let say you search for men only
SearchResponse sr = client.prepareSearch()
        .setQuery(QueryBuilders.termQuery("gender", "male"))
        .addAggregation(aggregation)
        .get();

Range Aggregation 範圍聚合

AggregationBuilder aggregation =
        AggregationBuilders
                .range("agg")
                .field("height")
                .addUnboundedTo(1.0f)               // from -infinity to 1.0 (excluded)
                .addRange(1.0f, 1.5f)               // from 1.0 to 1.5 (excluded)
                .addUnboundedFrom(1.5f);            // from 1.5 to +infinity

Date Range Aggregation 日期範圍聚合

AggregationBuilder aggregation =
        AggregationBuilders
                .dateRange("agg")
                .field("dateOfBirth")
                .format("yyyy")
                .addUnboundedTo("1950")    // from -infinity to 1950 (excluded)
                .addRange("1950", "1960")  // from 1950 to 1960 (excluded)
                .addUnboundedFrom("1960"); // from 1960 to +infinity

Ip Range Aggregation IP範圍聚合

AggregatorBuilder<?> aggregation =
        AggregationBuilders
                .ipRange("agg")
                .field("ip")
                .addUnboundedTo("192.168.1.0")             // from -infinity to 192.168.1.0 (excluded)
                .addRange("192.168.1.0", "192.168.2.0")    // from 192.168.1.0 to 192.168.2.0 (excluded)
                .addUnboundedFrom("192.168.2.0");          // from 192.168.2.0 to +infinity

Histogram Aggregation 直方圖聚合

AggregationBuilder aggregation =
        AggregationBuilders
                .histogram("agg")
                .field("height")
                .interval(1);

Date Histogram Aggregation 日期直方圖句

AggregationBuilder aggregation =
        AggregationBuilders
                .dateHistogram("agg")
                .field("dateOfBirth")
                .dateHistogramInterval(DateHistogramInterval.YEAR);

或者你想要設置一個十天的間隔

AggregationBuilder aggregation =
        AggregationBuilders
                .dateHistogram("agg")
                .field("dateOfBirth")
                .dateHistogramInterval(DateHistogramInterval.days(10));

Geo Distance Aggregation 地理距離聚合

AggregationBuilder aggregation =
        AggregationBuilders
                .geoDistance("agg", new GeoPoint(48.84237171118314,2.33320027692004))
                .field("address.location")
                .unit(DistanceUnit.KILOMETERS)
                .addUnboundedTo(3.0)
                .addRange(3.0, 10.0)
                .addRange(10.0, 500.0);

Geo Hash Grid Aggregation 地理哈希網格聚合

AggregationBuilder aggregation =
        AggregationBuilders
                .geohashGrid("agg")
                .field("address.location")
                .precision(4);

各聚合解釋可看官方文檔：文檔文檔