Date Histogram Aggregation

The aggregation that can be applied on date/time field values extracted from the documents

Builds fixed-size buckets based on the interval dynamically:

curl -XPOST 'localhost:9200/orders/_search?pretty=true' \
-H 'content-type: application/json' \
-d '
{
"size": 0,
"aggs": {
  "placedOnMonth": {
    "date_histogram" : {
      "field": "placedOn",
      "interval": "month",
      "format": "YYYY-MM"
     }
  }
}
}
'

Results:

{
...
"aggregations" : {
  "placedOnMonth" : {
    "buckets" : [ {
      "key_as_string" : "2016-01",
      "key" : 1451606400000,
      "doc_count" : 1
    }, {
      "key_as_string" : "2016-02",
      "key" : 1454284800000,
      "doc_count" : 0
    }, {
      "key_as_string" : "2016-03",
      "key" : 1456790400000,
      "doc_count" : 0
    }, {
...