如果你懂sql，请写一个查询来获取代码的值，例如sql查询等价和elasticsearch查询

POST /_sql/translate
{
  
  "query": "select name,surname from users"
}

结果是，请仔细查看includes键

{
  "size" : 1000,
  "_source" : {
    "includes" : [
      "name",
      "surname"
    ],
    "excludes" : [ ]
  },
  "sort" : [
    {
      "_doc" : {
        "order" : "asc"
      }
    }
  ]
}

在java中，你可以这样使用setFetchSource:

client.prepareSearch(index).setTypes(type)
            .setFetchSource(new String[] { "field1", "field2" }, null)

在Elasticsearch 5。X上述方法是不赞成的。 你可以使用_source方法，但是在某些情况下，存储一个字段是有意义的。例如，如果你有一个带有标题、日期和一个非常大的内容字段的文档，你可能只想检索标题和日期，而不必从一个大的_source字段中提取这些字段:

在这种情况下，你可以使用:

{  
   "size": $INT_NUM_OF_DOCS_TO_RETURN,
   "stored_fields":[  
      "doc.headline",
      "doc.text",
      "doc.timestamp_utc"
   ],
   "query":{  
      "bool":{  
         "must":{  
            "term":{  
               "doc.topic":"news_on_things"
            }
         },
         "filter":{  
            "range":{  
               "doc.timestamp_utc":{  
                  "gte":1451606400000,
                  "lt":1483228800000,
                  "format":"epoch_millis"
               }
            }
         }
      }
   },
   "aggs":{  

   }
}

有关如何为存储的字段建立索引，请参阅文档。 总是很高兴得到好评!

有几种方法可以用于实现特定领域的结果。 可以通过源方法。 根据我们的兴趣，另一个方法filter_path也可以用来接收更清晰、更概括的答案:

索引"index1"中的文档Json:

"hits" : [
  {
    "_index" : "index1",
    "_type" : "_doc",
    "_id" : "1",
    "_score" : 1,
    "_source" : {
      "year" : 2020,
      "created_at" : "2020-01-29",
      "url" : "www.github.com/mbarr0987",
      "name":"github"
    }
  }

查询:

GET index1/_search?filter_path=hits.hits._source.url
{
  "query": { 
        {"term": {"name":"github" }
    }
  }
}

输出:

{
  "hits" : {
    "hits" : [
      {
        "_source" : {
          "url" : "www.github.com/mbarr0987"
            }
          }
      ]
   }
}

REST API GET请求可以使用'_source'参数进行。

示例请求

http://localhost:9200/opt_pr/_search?q=SYMBOL:ITC AND OPTION_TYPE=CE AND TRADE_DATE=2017-02-10 AND EXPIRY_DATE=2017-02-23&_source=STRIKE_PRICE

响应

{
"took": 59,
"timed_out": false,
"_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
},
"hits": {
    "total": 104,
    "max_score": 7.3908954,
    "hits": [
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLc",
            "_score": 7.3908954,
            "_source": {
                "STRIKE_PRICE": 160
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLh",
            "_score": 7.3908954,
            "_source": {
                "STRIKE_PRICE": 185
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLi",
            "_score": 7.3908954,
            "_source": {
                "STRIKE_PRICE": 190
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLm",
            "_score": 7.3908954,
            "_source": {
                "STRIKE_PRICE": 210
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLp",
            "_score": 7.3908954,
            "_source": {
                "STRIKE_PRICE": 225
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLr",
            "_score": 7.3908954,
            "_source": {
                "STRIKE_PRICE": 235
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLw",
            "_score": 7.3908954,
            "_source": {
                "STRIKE_PRICE": 260
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uL5",
            "_score": 7.3908954,
            "_source": {
                "STRIKE_PRICE": 305
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLd",
            "_score": 7.381078,
            "_source": {
                "STRIKE_PRICE": 165
            }
        },
        {
            "_index": "opt_pr",
            "_type": "opt_pr_r",
            "_id": "AV3K4QTgNHl15Mv30uLy",
            "_score": 7.381078,
            "_source": {
                "STRIKE_PRICE": 270
            }
        }
    ]
}

}

response_filtering

所有REST api都接受一个filter_path参数 减少elasticsearch返回的响应。此参数取 用点符号表示的以逗号分隔的过滤器列表。

https://stackoverflow.com/a/35647027/844700