我也有同样的问题，我解决这个问题的方法是在文档分数上引入一个子聚合。然后，在我的外部聚合中，我按max_core聚合的名称进行了排序。

GET /my-index/my-type/_search

{
  "query": {
    "bool": {
      "should": [
        {
          "match": {
            "searchTerm": {
              "query": "style",
              "type": "boolean"
            }
          }
        },
        {
          "flt_field": {
            "searchTerm": {
              "like_text": "style"
            }
          }
        }
      ]
    }
  },
  "aggs": {
    "group_by_target_url": {
      "terms": {
        "field": "targetUrl",
        "order": {
          "max_score": "desc"
        }
      },
      "aggs": {
        "max_score": {
          "max": {
            "script": "_score"
          }
        }
      }
    }
  }
}

我按照这个链接上的说明操作：

http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/search-aggregations-bucket-terms-aggregation.html