elasticsearch计算唯一值的平均值

如何动态计算elasticsearch中唯一值的平均值？

{ "price" : 10000, "color" : "red" }
{ "price" : 20000, "color" : "red" }
{ "price" : 30000, "color" : "green" }
{ "price" : 15000, "color" : "blue" }
{ "price" : 12000, "color" : "green" }
{ "price" : 20000, "color" : "red" }
{ "price" : 80000, "color" : "red" }
{ "price" : 25000, "color" : "blue" }

在上面的数据中，如何获得“颜色”字段的唯一值以及每个唯一“颜色”字段的平均值？

Using a terms聚合 https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket-terms-aggregation.html找出独特的颜色值，然后avg子聚合 https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-metrics-avg-aggregation.html就可以了：

{
  "aggs": {
    "colors": {
      "terms": {
        "field": "color"
      },
      "aggs": {
        "average": {
          "avg": {
            "field": "price"
          }
        }
      }
    }
  }
}