elasticsearch aggregation sample by java. date histogram.

es_agg_datehistogram.java

/*
ES Aggregation to get result same as result from this SQL
SELECT  
DATE(create_at),fieldA,SUM(fieldB) 
from table   
group by DATE(create_at),fieldA;
*/
SearchRequestBuilder searchReq = client.prepareSearch("sample_index");
searchReq.setTypes("sample_types");
//例えばInterval.minutes(15)にすると15分ごとの集計ができる
DateHistogramBuilder dhb = AggregationBuilders.dateHistogram("my_datehistogram").field("create_at").interval(DateHistogram.Interval.days(1));
TermsBuilder termsb_fa = AggregationBuilders.terms("my_fieldA").field("fieldA").size(100);
termsb_fa.subAggregation(AggregationBuilders.sum("my_sum_fieldB").field("fieldB"));
dhb.subAggregation(termsb_fa)

searchReq.setQuery(QueryBuilders.matchAllQuery()).addAggregation(dhb);
SearchResponse searchRes = searchReq.execute().actionGet();

DateHistogram dateHist = searchRes.getAggregations().get("my_datehistogram");
for (DateHistogram.Bucket dateBucket : dateHist.getBuckets()) {
	//DATE(create_at)
	String create_at = dateentry.getKey();
	Terms fieldATerms = dateBucket.getAggregations().get("my_fieldA");
	for (Terms.Bucket filedABucket : fieldATerms.getBuckets()) {
		//fieldA
		String fieldAValue = filedABucket.getKey();
		
		//SUM(fieldB)
		Sum sumagg = filedABucket.getAggregations().get("my_sum_fieldB");
		long sumFieldB = (long)sumagg.getValues();
	}
}