我需要做的是按位置提升文档（越近越好）。locations是嵌套类型。
工作正常除了如果文档中缺少locations，Elasticsearch不会返回文档。如果缺少字段，Elasticsearch应该将文档视为完美命中。如何实现这一点？
我的查询：

{
   "sort": [
      {
         "_score": "desc"
      }
   ],
   "query": {
      "function_score": {
         "query": {
            "bool": {
               "must_not": [],
               "should": [
                  {
                     "nested": {
                        "path": "locations",
                        "query": {
                           "function_score": {
                              "score_mode": "sum",
                              "functions": [
                                 {
                                    "gauss": {
                                       "locations.coordinates": {
                                          "origin": {
                                             "lat": "50.1078852",
                                             "lon": "15.0385376"
                                          },
                                          "scale": "100km",
                                          "offset": "20km",
                                          "decay": "0.5"
                                       }
                                    }
                                 }
                              ]
                           }
                        }
                     }
                  }
               ]
            }
         }
      }
   }
}

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顺便说一句：我正在使用Elasticsearch 5.0