分组查询

///////////////////FOR JSON ////////////////////////////
{
   "query": {
       "match_all": {}
   },
   "aggs": {
       "lv": {
           "terms": {
               "field": "lv"
           }
       }
   },
   "size": 0
}
{
   "query": {
       "match_all": {}
   },
   "size": 0,
   "aggs": {
       "group_by_cl": {
           "terms": {
               "field": "_index"
           }
       }
   }
}
//////////////////////////FOR PHP////////////////////
$query = new \Elastica\Query(new \Elastica\Query\MatchAll());
       // More complex aggregation, we get categories for each month
       $dateAggregation = new \Elastica\Aggregation\DateHistogram('dateHistogram','publishedAt','month');
       $dateAggregation->setFormat("dd-MM-YYYY");
       $categoryAggregation = new \Elastica\Aggregation\Terms('category');
       $categoryAggregation->setField("category");
       $dateAggregation->addAggregation($categoryAggregation);
       $query->addAggregation($dateAggregation);
       // we don't need any results, only the statistics
       $query->setSize(0);