把Elasticsearch当成Database用，因为Elasticsearch不支持SQL，就需要把SQL转换成代码实现。
1.按某个field group by查询count
SELECT fieldA, COUNT(fieldA) from table WHERE fieldC = "hoge" AND fieldD = "huga" AND fieldB > 10 AND fieldB < 100 group by fieldA;
对应的java code:
SearchRequestBuilder searchReq = client.prepareSearch("sample_index");
searchReq.setTypes("sample_types");
TermsBuilder termsb = AggregationBuilders.terms("my_fieldA").field("fieldA").size(100);BoolFilterBuilder bf = FilterBuilders.boolFilter();
TermFilterBuilder tf_fieldC = FilterBuilders.termFilter("fieldC","hoge");
TermFilterBuilder tf_fieldD = FilterBuilders.termFilter("fieldD","huga");
bf.must(tf_fieldC);
bf.must(tf_fieldD);RangeFilterBuilder rangefieldBFilter = FilterBuilders.rangeFilter("fieldB").gt(10).lt(100);searchReq.setQuery(QueryBuilders.filteredQuery(QueryBuilders.matchAllQuery(),FilterBuilders.andFilter(bf, rangefieldBFilter))).addAggregation(termsb);
SearchResponse searchRes = searchReq.execute().actionGet();Terms fieldATerms = searchRes.getAggregations().get("my_fieldA");
for (Terms.Bucket filedABucket : fieldATerms.getBuckets()) {//fieldAString fieldAValue = filedABucket.getKey();//COUNT(fieldA)long fieldACount = filedABucket.getDocCount();
}
2. 按某个field 和 date group by 并查询另一个filed的sum，时间统计图，时间间隔是1天。
SELECT DATE(create_at), fieldA, SUM(fieldB) from table group by DATE(create_at), fieldA;
对应的java code:
SearchRequestBuilder searchReq = client.prepareSearch("sample_index");
searchReq.setTypes("sample_types");
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()) {//fieldAString fieldAValue = filedABucket.getKey();//SUM(fieldB)Sum sumagg = filedABucket.getAggregations().get("my_sum_fieldB");long sumFieldB = (long)sumagg.getValues();}
}
3. 按两个field group by并查询第三个filed的sum
SELECT fieldA, fieldC, SUM(fieldB) from table group by fieldA, fieldC;
对应的java code:
SearchRequestBuilder searchReq = client.prepareSearch("sample_index");
searchReq.setTypes("sample_types");TermsBuilder termsb_fa = AggregationBuilders.terms("my_fieldA").field("fieldA").size(100);
TermsBuilder termsb_fc = AggregationBuilders.terms("my_fieldC").field("fieldC").size(50);termsb_fc.subAggregation(AggregationBuilders.sum("my_sum_fieldB").field("fieldB"));
termsb_fa.subAggregation(termsb_fc)searchReq.setQuery(QueryBuilders.matchAllQuery()).addAggregation(termsb_fa);
SearchResponse searchRes = searchReq.execute().actionGet();Terms fieldATerms = searchRes.getAggregations().get("my_fieldA");
for (Terms.Bucket filedABucket : fieldATerms.getBuckets()) {//fieldAString fieldAValue = filedABucket.getKey();Terms fieldCTerms = filedABucket.getAggregations().get("my_fieldC");for (Terms.Bucket filedCBucket : fieldCTerms.getBuckets()) {//fieldCString fieldCValue = filedCBucket.getKey();//SUM(fieldB)Sum sumagg = filedCBucket.getAggregations().get("my_sum_fieldB");long sumFieldB = (long)sumagg.getValues();}
}
4. 按某个filed group by 并查询count、sum 和 average
SELECT fieldA, COUNT(fieldA), SUM(fieldB), AVG(fieldB) from table group by fieldA;
对应的java code:
SearchRequestBuilder searchReq = client.prepareSearch("sample_index");
searchReq.setTypes("sample_types");TermsBuilder termsb = AggregationBuilders.terms("my_fieldA").field("fieldA").size(100);
termsb.subAggregation(AggregationBuilders.sum("my_sum_fieldB").field("fieldB"));
termsb.subAggregation(AggregationBuilders.avg("my_avg_fieldB").field("fieldB"));searchReq.setQuery(QueryBuilders.matchAllQuery()).addAggregation(termsb);
SearchResponse searchRes = searchReq.execute().actionGet();
Terms fieldATerms = searchRes.getAggregations().get("my_fieldA");
for (Terms.Bucket filedABucket : fieldATerms.getBuckets()) {//fieldAString fieldAValue = filedABucket.getKey();//COUNT(fieldA)long fieldACount = filedABucket.getDocCount();//SUM(fieldB)Sum sumagg = filedABucket.getAggregations().get("my_sum_fieldB");long sumFieldB = (long)sumagg.getValues();//AVG(fieldB)Avg avgagg = filedABucket.getAggregations().get("my_avg_fieldB");double avgFieldB = avgagg.getValues();
}
5. 按某个field group by 并按另一个filed的Sum排序，获取前10
SELECT fieldA, SUM(fieldB) from table WHERE fieldC = "hoge" group by fieldA order by SUM(fieldB) DESC limit 10;
对应的java code:
QueryBuilder termsc = QueryBuilders.termQuery("fieldC","hoge");
QueryBuilder queryBuilder = QueryBuilders.boolQuery().must(termsc);
TermsAggregationBuilder aggregationBuilder = AggregationBuilders.terms("my_fieldA").field("fieldA").size(10);
aggregationBuilder.subAggregation(AggregationBuilders.sum("my_sum_fieldB").field("fieldB"));
aggregationBuilder.order(Order.aggregation("my_sum_fieldB", false));
SearchResponse searchResponse = client.prepareSearch("sample_index").setQuery(queryBuilder).addAggregation(aggregationBuilder).execute().actionGet();
Terms terms = searchResponse.getAggregations().get("my_fieldA");
for (Terms.Bucket entry : terms.getBuckets()) {String fieldAValue = entry.getKey().toString();Sum sumagg = entry.getAggregations().get("my_sum_fieldB");double fieldValue = sumagg.getValue();
}
代码在GitHub上：https://github.com/luxiaoxun/Code4Java
本文转自阿凡卢博客园博客，原文链接：http://www.cnblogs.com/luxiaoxun/p/6826211.html，如需转载请自行联系原作者
