Count buckets returned by sub aggregation

Question

I need to count the number of buckets from a result set returned by pipe aggregation. Problem is that my query that is using script selector here:

POST visitor_c         


        

Answer 1

You can make use of Stats Bucket Aggregation to get the count of buckets.

Below is how your query would be.

Aggregation Query:

POST visitor_carts/_search
{
  "size": 0,
  "aggs": {
    "visitors": {
      "terms": {
        "field" : "visitor_id"
      },
      "aggs": {
        "one_purchase": {
          "bucket_selector": {
            "buckets_path": {
              "nb_purchases": "_count"
            },
            "script": "params.nb_purchases == 3"
          }
        }
      }
    },
    "mybucketcount":{
      "stats_bucket": {
        "buckets_path":"visitors._count"
      }
    }
  }
}

Aggregation Result:

{
  "took": 1,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 8,
    "max_score": 0,
    "hits": []
  },
  "aggregations": {
    "visitors": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
        {
          "key": "2",
          "doc_count": 3
        },
        {
          "key": "3",
          "doc_count": 3
        }
      ]
    },
    "mybucketcount": {
      "count": 2,              <---- This is the count you are looking for
      "min": 3,
      "max": 3,
      "avg": 3,
      "sum": 6
    }
  }
}

Let me know if this helps!