How to filter terms aggregation

Question

Currently I have something like this

aggs: {
  categories: {
    terms: {
      field: 'category'
    }
  }
}

and this is giving me number of products in each category. But I have additional condition. I need to get number of products in each category which are not sold already, so I need to perform filter on terms somehow.

Is there some elegant way of doing this using aggregation framework, or I need to write filtered query?

Thank you

Answer 1

You can merge between Terms Aggregation and Filter Aggregation, and this is how it should look: (tested)

    aggs: {
      categories: {            
        filter: {term: {sold: true}},
        aggs: {
          names: {
            terms: {field: 'category'}
          }
        }
      }
    }

You can add also more conditions to the filter, I hope this helps.

Answer 2

Just to add to the other answer, you can also use a nested query. This is similar to what I had to do. I'm using Elasticsearch 5.2.

From the docs, here is the basic syntax:

"aggregations" : {
    "<aggregation_name>" : {
        "<aggregation_type>" : {
            <aggregation_body>
        }
        [,"aggregations" : { [<sub_aggregation>]+ } ]?
    }
    [,"<aggregation_name_2>" : { ... } ]*
}

This is how I implemented it:

GET <path> core_data/_search
{
  "aggs": {
    "NAME": {
      "nested": {
        "path": "ATTRIBUTES"
      },
      "aggs": {
        "NAME": {
          "filter": {
            "term": {
              "ATTRIBUTES.ATTR_TYPE": "EDUCATION_DEGREE"
            }
          },
          "aggs": {
            "NAME": {
              "terms": {
                "field": "ATTRIBUTES.DESCRIPTION",
                "size": 100
              }
            }
          }
        }
      }
    }
  }
}

This filtered the data down to one bucket, which is what I needed.