elasticsearch版本：5.6.16，lucene\u版本：6.6.1
我想按elasticsearch中的聚合字段对点击进行排序。
我想排序的字段是bucket聚合组按item id的savings pct。
有没有办法将字段放入“\u source”以便我可以在排序脚本中使用它？
请注意，查询示例中的重要位是“groupbyitem”和“source”以及“sort”

{
    "query": {
        "bool": {
            "must": [],
            "should": [],
            "filter": [
                {
                    "terms": {
                        "item_type": [
                            "helmets_clothes"
                        ]
                    }
                }

            ]
        }
    },
    "aggs": {
        "min_price_eur": {
            "min": {
                "field": "item_price_eur",
                "missing": 0
            }
        },
        "max_price_eur": {
            "max": {
                "field": "item_price_eur",
                "missing": 0
            }
        },
"group_by_item_id": {
            "terms": {
                "field": "same_item_id",
                "size": 100
            },
            "aggs": {
                "average_price": {
                    "avg": {
                        "field": "item_price_eur"
                    }
                },
                "min_price": {
                    "min": {
                        "field": "item_price_eur"
                    }
                }, 
            "savings_pct": {
          "bucket_script": {
            "buckets_path": {
              "avg_price": "average_price",
                            "total_prices": "_count",
                            "min_price": "min_price"

            },
            "script": "100-(params.min_price / params.avg_price) * 100"
          }
        }
            }
        }
    },
    "_source": [
        "item_url"
    ],
    "sort": [
                {
            "_script" : {
            "type" : "number",
            "script" : {
                                "lang": "painless",
                "inline": "doc['prices_count'].value == 5 ? 100 - (doc['min_price_eur'].value / doc['max_price_eur'].value) * 100 : 0"
            },
            "order" : "asc"
                    }
                }
    ]
}