Calculate the average age by country of residence in Elasticsearch

Question

Elasticsearch allows for nested aggregations. What is the syntax for calculating the average age by country of residence?

Accepted Answer

```
POST /_search
{
  "aggs": {
    "genres": {
      "terms": { "field": "country" },
      “aggs”: { 
          “avg_age”: { “avg”: { “field”: “age” }}
      }
    }
  }
}
```

Answer

```
POST /_search
{
  "aggs": {
    "genres": {
      "filter": { "field": "country" },
      “aggs”: { 
          “avg_age”: { “avg”: { “field”: “age” }}
      }
    }
  }
}

```

Answer

```
POST /_search
{
  "aggs": {
    "genres": {
      "terms": { "field": "country" },
       “avg_age”: { “avg”: { “field”: “age” }}
    }
  }
}
```

Answer

```
POST /_search
{
  "aggs": {
    "genres": {
      "terms": { "field": "country" },
      “sub_aggs”: { 
          “avg_age”: { “avg”: { “field”: “age” }}
      }
    }
  }
}
```

Question from the Elasticsearch test

Calculate the average age by country of residence in Elasticsearch