CODEWITHSUNDEEP
elasticsearchnestedelasticsearch-aggregation
Steve
Steve

Reputation: 149

Count number of elements per nested field in Elastic Search

I'm new with Elastic Search. I have documents in Elastic Search that contain nested fields like this:

Document 1:

"Volume": [
{
"partition": "s1",
"type": "west"
}
{
"partition": "s2",
"type": "south"
}
]

Document 2:

"Volume": [
{
"partition": "a2",
"type": "north"
}
]

Document 3:

"Volume": [
{
"partition": "f3",
"type": "north"
}
{
"partition": "a1",
"type": "south"
}
]

and so on. I need to count the number of "type" fields, so the expected result would be: "west": 1 "south": 2 "north":2

I used nested aggregation, like this:

"size":0,
  "aggs": {
    "nested_properties": {
      "nested": {
        "path": "Volume"
      },
      "aggs": {
        "count": {
          "cardinality": {
            "field": "Volume.type"
              }
          }
      }
   }
}

But the result is:

"aggregations": {
  "nested_properies": {
    "doc_count": 123456,
      "count": {
        "value": 9
      }
   }
}

How can I count the number of entries for each "type" subfield?

Upvotes: 0

Views: 188

Answers (1)

rabbitbr
rabbitbr

Reputation: 3261

You can use Term Aggregation.

Like this:

{
  "size": 0,
  "aggs": {
    "groups": {
      "nested": {
        "path": "Volume"
      },
      "aggs": {
        "NAME": {
          "terms": {
            "field": "Volume.type.keyword",
            "size": 10
          }
        }
      }
    }
  }
}

Response:

 "aggregations": {
    "groups": {
      "doc_count": 5,
      "NAME": {
        "doc_count_error_upper_bound": 0,
        "sum_other_doc_count": 0,
        "buckets": [
          {
            "key": "north",
            "doc_count": 2
          },
          {
            "key": "south",
            "doc_count": 2
          },
          {
            "key": "west",
            "doc_count": 1
          }
        ]
      }
    }
  }

Upvotes: 1

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