如何在ES中找到某字段首次出现的值？

{

    "query": {

        "range" : {

            "time" : {

                "gte" : start_time,

                "lte" : end_time,

            }

        }

    },

    "size":0,

     "aggs": {

                "top_time_hits": {

                    "top_hits": {

                        "sort": [

                            {

                                "time": {

                                    "order": "asc"

                                }

                            }

                        ],

                        "_source": {

                            "includes": [ "time", "url" ]

                        },

                        "size" : 1

                    }

                }

            }

        }

    }

}