Elasticsearch习题 4.Script脚本查询 - 在码圈-专注编程技术分享-代码改变未来，努力coding

Task1

数据

索引Task1保存了公安案件的嫌疑人信息


PUT test_index/_bulk?refresh
{"index": {"_id": 1}}
{"ajbh":"12345","ajmc":"li'an'an'jian","lasj":"2020/05/21 13:25:23","jsbax_sjjh2_xz_ryjbxx_cleaning":[{"XM":"zhangsan","NL":"30","SF":"nan"},{"XM":"lisi","NL":"31","SF":"nan"},{"XM":"wangwu","NL":"30","SF":"nv"},{"XM":"zhaoliu","NL":23,"SF":"nan"}]}
{"index":{"_id":2}}
{"ajbh":"563245","ajmc":"jie'an'shi'jian","lasj":"2020/05/21 13:25:23","jsbax_sjjh2_xz_ryjbxx_cleaning":[{"XM":"zhangsan2","NL":"30","SF":"nan"},{"XM":"lisi2","NL":"31","SF":"nan"},{"XM":"wangwu2","NL":"30","SF":"nv"},{"XM":"zhaoliu2","NL":"23","SF":"nv"}]}
{"index":{"_id":3}}
{"ajbh":"12345","ajmc":"li'an'an'jian","lasj":"2020/05/21 13:25:23","jsbax_sjjh2_xz_ryjbxx_cleaning":[{"XM":"zhangsan3","NL":"30","SF":"nan"},{"XM":"lisi3","NL":"31","SF":"nan"},{"XM":"wangwu3","NL":"30","SF":"nv"},{"XM":"zhaoliu3","NL":"23","SF":"nan"}]}

要求：

统计nan性嫌疑人的数量（注意，是统计嫌疑人数量，而不是文档数量，结果应为 8 ）

答案：

GET test_index/_search
{
  "size": 0, 
  "aggs": {
    "nan_xianyifan_count": {
      "sum": {
        "script": {
          "lang": "painless", 
          "source": """
           int count = 0;
           for(int i=0;i<params['_source']['jsbax_sjjh2_xz_ryjbxx_cleaning'].length;i++){
             if(params['_source']['jsbax_sjjh2_xz_ryjbxx_cleaning'][i]['SF'] == 'nan'){
               count++;
             }
           }
           return count;
           """
        }
      }
    }
  }
}

Task2

要求

创建一个名为calculate_discount的脚本模板，计算一个新的discount_price, 其值为打折后的价钱，

使用脚本模板分别计算并输出product索引中商品的原价price，9折、8折的价格。

答案:

POST _scripts/calculate_discount
{
  "script": {
    "lang": "painless",
    "source": "doc['price'].value * params['discount']"
  }
}

GET product/_search
{
  "script_fields": {
    "source_price": {
      "script": {
        "id": "calculate_discount",
        "params": {
          "discount": 1
        }
      }
    },
    "9_discount_price": {
      "script": {
        "id": "calculate_discount",
        "params": {
          "discount": 0.9
        }
      }
    },
    "8_discount_price": {
      "script": {
        "id": "calculate_discount",
        "params": {
          "discount": 0.8
        }
      }
    }
  }
}

总结

对于scripting 坑还是比较多的
大部分在两种语言上 painless 和 expression

expression 可能会写成 expressions
在进行计算时 painless计算必须带value 而 expression 则带不带都行
在使用 params时，painless可以使用params.参数名称或 params['参数名称'] 而 expression则需要直接xxx
在update中要使用ctx上下文来调用原字段
查询时要使用 doc['字段'] (注意这里必须加单引号), 对于复杂的类型要使用 params['_source']['字段']