70 lines
2.3 KiB
Plaintext
70 lines
2.3 KiB
Plaintext
[[java-aggs-bucket-datehistogram]]
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==== Date Histogram Aggregation
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Here is how you can use
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{ref}/search-aggregations-bucket-datehistogram-aggregation.html[Date Histogram Aggregation]
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with Java API.
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===== Prepare aggregation request
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Here is an example on how to create the aggregation request:
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[source,java]
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--------------------------------------------------
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AggregationBuilder aggregation =
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AggregationBuilders
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.dateHistogram("agg")
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.field("dateOfBirth")
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.dateHistogramInterval(DateHistogramInterval.YEAR);
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--------------------------------------------------
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Or if you want to set an interval of 10 days:
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[source,java]
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--------------------------------------------------
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AggregationBuilder aggregation =
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AggregationBuilders
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.dateHistogram("agg")
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.field("dateOfBirth")
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.dateHistogramInterval(DateHistogramInterval.days(10));
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--------------------------------------------------
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===== Use aggregation response
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Import Aggregation definition classes:
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[source,java]
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--------------------------------------------------
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import org.elasticsearch.search.aggregations.bucket.histogram.Histogram;
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--------------------------------------------------
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[source,java]
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--------------------------------------------------
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// sr is here your SearchResponse object
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Histogram agg = sr.getAggregations().get("agg");
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// For each entry
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for (Histogram.Bucket entry : agg.getBuckets()) {
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DateTime key = (DateTime) entry.getKey(); // Key
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String keyAsString = entry.getKeyAsString(); // Key as String
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long docCount = entry.getDocCount(); // Doc count
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logger.info("key [{}], date [{}], doc_count [{}]", keyAsString, key.getYear(), docCount);
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}
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--------------------------------------------------
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This will basically produce for the first example:
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[source,text]
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--------------------------------------------------
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key [1942-01-01T00:00:00.000Z], date [1942], doc_count [1]
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key [1945-01-01T00:00:00.000Z], date [1945], doc_count [1]
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key [1946-01-01T00:00:00.000Z], date [1946], doc_count [1]
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...
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key [2005-01-01T00:00:00.000Z], date [2005], doc_count [1]
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key [2007-01-01T00:00:00.000Z], date [2007], doc_count [2]
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key [2008-01-01T00:00:00.000Z], date [2008], doc_count [3]
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--------------------------------------------------
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