23 款实用的 Elasticsearch 查询示例

ElasticSearch是一个基于Lucene的搜索服务器，它是用Java开发的，并作为Apache许可条款下的开放源码发布，是当前流行的企业级搜索引擎。本文介绍了几种常用的Elasticsearch查询方式，并分别进行了举例，希望它们对你有帮助。（注：文章翻译自Tim Ojo的 23 Useful Elasticsearch Example Queries 。 若有翻译不到位的地方，欢迎大家进行指正。喜欢的也不要忘了打赏、点赞、收藏哦：)）

为了介绍Elasticsearch中的不同查询类型，我们将对带有下列字段的文档进行搜索：title（标题），authors（作者），summary（摘要），release date（发布时间）以及number of reviews（评论数量）。

首先，让我们创建一个新的索引，并通过 bulk API 查询文档：

PUT /bookdb_index

    { "settings": { "number_of_shards": 1 }}

POST /bookdb_index/book/_bulk

    { "index": { "_id": 1 }}

    { "title": "Elasticsearch: The Definitive Guide", "authors": ["clinton gormley", "zachary tong"], "summary" : "A distibuted real-time search and analytics engine", "publish_date" : "2015-02-07", "num_reviews": 20, "publisher": "oreilly" }

    { "index": { "_id": 2 }}

    { "title": "Taming Text: How to Find, Organize, and Manipulate It", "authors": ["grant ingersoll", "thomas morton", "drew farris"], "summary" : "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization", "publish_date" : "2013-01-24", "num_reviews": 12, "publisher": "manning" }

    { "index": { "_id": 3 }}

    { "title": "Elasticsearch in Action", "authors": ["radu gheorge", "matthew lee hinman", "roy russo"], "summary" : "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms", "publish_date" : "2015-12-03", "num_reviews": 18, "publisher": "manning" }

    { "index": { "_id": 4 }}

    { "title": "Solr in Action", "authors": ["trey grainger", "timothy potter"], "summary" : "Comprehensive guide to implementing a scalable search engine using Apache Solr", "publish_date" : "2014-04-05", "num_reviews": 23, "publisher": "manning" }

举例

基本匹配查询

有两种方式执行基本全文（匹配）查询：使用Search Lite API，它将搜索参数作为URL的一部分传递；使用完整的JSON请求消息体，它允许你使用完整的Elasticsearch DSL。

以下是基本的匹配查询，在所有字段中查询字符串“guide”：

GET /bookdb_index/book/_search?q=guide

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.28168046,

        "_source": {

          "title": "Elasticsearch: The Definitive Guide",

          "authors": [

            "clinton gormley",

            "zachary tong"

          ],

          "summary": "A distibuted real-time search and analytics engine",

          "publish_date": "2015-02-07",

          "num_reviews": 20,

          "publisher": "manning"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.24144039,

        "_source": {

          "title": "Solr in Action",

          "authors": [

            "trey grainger",

            "timothy potter"

          ],

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "publish_date": "2014-04-05",

          "num_reviews": 23,

          "publisher": "manning"

        }

      }

    ]

这个查询的完整消息体如下，它产生的结果与上述查询相同：

{

    "query": {

        "multi_match" : {

            "query" : "guide",

            "fields" : ["_all"]

        }

    }

}

作为对多个字段运行相同查询的简便方法，multi_match关键字可以用在match关键字的位置。fields属性指定要查询的字段，在这种情况下，我们要对文档中的所有字段进行查询。

两种API都允许你指定你想查询的字段。比如，指定搜索标题字段中含“in Action”的图书：

GET /bookdb_index/book/_search?q=title:in action

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.6259885,

        "_source": {

          "title": "Solr in Action",

          "authors": [

            "trey grainger",

            "timothy potter"

          ],

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "publish_date": "2014-04-05",

          "num_reviews": 23,

          "publisher": "manning"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 0.5975345,

        "_source": {

          "title": "Elasticsearch in Action",

          "authors": [

            "radu gheorge",

            "matthew lee hinman",

            "roy russo"

          ],

          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",

          "publish_date": "2015-12-03",

          "num_reviews": 18,

          "publisher": "manning"

        }

      }

    ]

然而，完整的DSL能提供更大的灵活性，让你可以创建更复杂的查询（我们在下文会提到）以及指定查询结果的返回方式。在下列示例中，我们指定了要返回的结果数量、偏移位置（对分页有用）、要返回的文档字段和高亮显示的项。

POST /bookdb_index/book/_search

{

    "query": {

        "match" : {

            "title" : "in action"

        }

    },

    "size": 2,

    "from": 0,

    "_source": [ "title", "summary", "publish_date" ],

    "highlight": {

        "fields" : {

            "title" : {}

        }

    }

}

[Results]

"hits": {

    "total": 2,

    "max_score": 0.9105287,

    "hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 0.9105287,

        "_source": {

          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",

          "title": "Elasticsearch in Action",

          "publish_date": "2015-12-03"

        },

        "highlight": {

          "title": [

            "Elasticsearch <em>in</em> <em>Action</em>"

          ]

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.9105287,

        "_source": {

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        },

        "highlight": {

          "title": [

            "Solr <em>in</em> <em>Action</em>"

          ]

        }

      }

    ]

  }

注：对于多词（multi-word）查询，相应的匹配（match）查询允许你指定是否使用and运算符，而不是默认使用or运算符。你也可以指定minimum_should_match选项来调整返回结果的相关性。详细信息可以在 Elasticsearch 指南 中找到。

多字段查询

为了在一次查询中查找多个字段（如，在title和summary中查找相同的字符串），你使用了multi_match查询：

POST /bookdb_index/book/_search

{

    "query": {

        "multi_match" : {

            "query" : "elasticsearch guide",

            "fields": ["title", "summary"]

        }

    }

}

[Results]

"hits": {

    "total": 3,

    "max_score": 0.9448582,

    "hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.9448582,

        "_source": {

          "title": "Elasticsearch: The Definitive Guide",

          "authors": [

            "clinton gormley",

            "zachary tong"

          ],

          "summary": "A distibuted real-time search and analytics engine",

          "publish_date": "2015-02-07",

          "num_reviews": 20,

          "publisher": "manning"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 0.17312013,

        "_source": {

          "title": "Elasticsearch in Action",

          "authors": [

            "radu gheorge",

            "matthew lee hinman",

            "roy russo"

          ],

          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",

          "publish_date": "2015-12-03",

          "num_reviews": 18,

          "publisher": "manning"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.14965448,

        "_source": {

          "title": "Solr in Action",

          "authors": [

            "trey grainger",

            "timothy potter"

          ],

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "publish_date": "2014-04-05",

          "num_reviews": 23,

          "publisher": "manning"

        }

      }

    ]

  }

注：上面的查询匹配了3个结果，因为单词“guide”在summary（摘要）中有出现。

Boosting 算法

有时候，我们在多个字段中进行搜索，可能会希望提高某个字段中的权重。如，在下列设计示例中，我们将summary字段的权重提高三倍，以提高这个字段的重要性，从而增强文档 _id 4的相关性。

POST /bookdb_index/book/_search

{

    "query": {

        "multi_match" : {

            "query" : "elasticsearch guide",

            "fields": ["title", "summary^3"]

        }

    },

    "_source": ["title", "summary", "publish_date"]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.31495273,

        "_source": {

          "summary": "A distibuted real-time search and analytics engine",

          "title": "Elasticsearch: The Definitive Guide",

          "publish_date": "2015-02-07"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.14965448,

        "_source": {

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 0.13094766,

        "_source": {

          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",

          "title": "Elasticsearch in Action",

          "publish_date": "2015-12-03"

        }

      }

    ]

注：Boosting并不意味着计算的权重会被boost因子翻倍。实际的boost值会进行一些规范化和内部优化。想了解更多boost工作原理的信息，可参考 Elasticsearch指南 。

Bool 查询

为获得更具相关性和更具体的查询结果，AND / OR / NOT运算符可在我们的搜索查询进行微调。这在搜索API中作为bool查询实现。bool查询接受must参数（等效于AND），must_not参数（等效于NOT），should参数（等效于OR）。比如，我想查询标题中带有“Elasticsearch” 或（OR） “Solr”的书，并且（AND）是由“clinton gormley”创作，而不是（NOT） “radu gheorge”。

POST /bookdb_index/book/_search

{

    "query": {

        "bool": {

            "must": {

                "bool" : { "should": [

                      { "match": { "title": "Elasticsearch" }},

                      { "match": { "title": "Solr" }} ] }

            },

            "must": { "match": { "authors": "clinton gormely" }},

            "must_not": { "match": {"authors": "radu gheorge" }}

        }

    }

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.3672021,

        "_source": {

          "title": "Elasticsearch: The Definitive Guide",

          "authors": [

            "clinton gormley",

            "zachary tong"

          ],

          "summary": "A distibuted real-time search and analytics engine",

          "publish_date": "2015-02-07",

          "num_reviews": 20,

          "publisher": "oreilly"

        }

      }

    ]

注：如你所见，bool查询囊括所有其他的搜索类型，包括其他类型的bool查询，以构建复杂和深层嵌套的查询体系。

模糊查询

模糊匹配可以在匹配和多重匹配查询上启用以捕获拼写错误。模糊程度由原始词之间的Levenshtein距离决定。

POST /bookdb_index/book/_search

{

    "query": {

        "multi_match" : {

            "query" : "comprihensiv guide",

            "fields": ["title", "summary"],

            "fuzziness": "AUTO"

        }

    },

    "_source": ["title", "summary", "publish_date"],

    "size": 1

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.5961596,

        "_source": {

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        }

      }

    ]

注：当术语长度大于5个字符时，"AUTO"的模糊值等同于指定值“2”。但是，80％的人类拼写错误的编辑距离为1，所以，将模糊值设置为“1”可能会提高您的整体搜索性能。更多详细信息，请参阅Elasticsearch指南中的“ 排版和拼写错误 ”（ Typos and Misspellings ）章节。

通配符查询

通配符查询允许你指定匹配的模式，而不是整个术语。？ 匹配任何字符，*匹配零个或多个字符。例如，要查找名称以字母't'开头的所有作者的记录：

POST /bookdb_index/book/_search

{

    "query": {

        "wildcard" : {

            "authors" : "t*"

        }

    },

    "_source": ["title", "authors"],

    "highlight": {

        "fields" : {

            "authors" : {}

        }

    }

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 1,

        "_source": {

          "title": "Elasticsearch: The Definitive Guide",

          "authors": [

            "clinton gormley",

            "zachary tong"

          ]

        },

        "highlight": {

          "authors": [

            "zachary <em>tong</em>"

          ]

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "2",

        "_score": 1,

        "_source": {

          "title": "Taming Text: How to Find, Organize, and Manipulate It",

          "authors": [

            "grant ingersoll",

            "thomas morton",

            "drew farris"

          ]

        },

        "highlight": {

          "authors": [

            "<em>thomas</em> morton"

          ]

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 1,

        "_source": {

          "title": "Solr in Action",

          "authors": [

            "trey grainger",

            "timothy potter"

          ]

        },

        "highlight": {

          "authors": [

            "<em>trey</em> grainger",

            "<em>timothy</em> potter"

          ]

        }

      }

    ]

正则查询

正则查询允许你指定比通配符查询更复杂的查询模式。

POST /bookdb_index/book/_search

{

    "query": {

        "regexp" : {

            "authors" : "t[a-z]*y"

        }

    },

    "_source": ["title", "authors"],

    "highlight": {

        "fields" : {

            "authors" : {}

        }

    }

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 1,

        "_source": {

          "title": "Solr in Action",

          "authors": [

            "trey grainger",

            "timothy potter"

          ]

        },

        "highlight": {

          "authors": [

            "<em>trey</em> grainger",

            "<em>timothy</em> potter"

          ]

        }

      }

    ]

匹配短语查询

匹配短语查询要求查询字符串中的所有字词都在文档中存在，要遵循查询字符串的指定顺序还要彼此接近。默认情况下，术语要求彼此相同，但你可以指定slop值，进行文档匹配时，该值可以指定词的距离。

POST /bookdb_index/book/_search

{

    "query": {

        "multi_match" : {

            "query": "search engine",

            "fields": ["title", "summary"],

            "type": "phrase",

            "slop": 3

        }

    },

    "_source": [ "title", "summary", "publish_date" ]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.22327082,

        "_source": {

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.16113183,

        "_source": {

          "summary": "A distibuted real-time search and analytics engine",

          "title": "Elasticsearch: The Definitive Guide",

          "publish_date": "2015-02-07"

        }

      }

    ]

注：在上述例子中，对于非短语类型查询，文档_id 1通常会以较高的权重出现在文档_id 4之前，因为其字段长度更加短。然而，作为短语查询，术语的接近度也需要考虑在内，因此文档_id 4权重会更高。

匹配短语前缀查询

匹配短语前缀查询在查询时提供“自动搜索”功能（search-as-you-type）或者说词穷时的自动补充功能，你无需以任何方式准备数据。和match_phrase查询一样，它接受slop参数，使得字的顺序和相对位置的调整不那么死板。它还接受max_expansions参数，以限制匹配的术语数量，减少资源强度。

POST /bookdb_index/book/_search

{

    "query": {

        "match_phrase_prefix" : {

            "summary": {

                "query": "search en",

                "slop": 3,

                "max_expansions": 10

            }

        }

    },

    "_source": [ "title", "summary", "publish_date" ]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.5161346,

        "_source": {

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.37248808,

        "_source": {

          "summary": "A distibuted real-time search and analytics engine",

          "title": "Elasticsearch: The Definitive Guide",

          "publish_date": "2015-02-07"

        }

      }

    ]

注：查询时（query-time）搜索类型具有性能成本。 所以你可以选择将索引时（index-time）搜索作为搜索类型。更多详情，请查看 Completion Suggester API 或使用 Edge-Ngram filters 获取。

查询字符串查询

查询字符串查询提供了以简明的速记语法执行multi_match查询，bool查询，boosting查询，模糊匹配查询，通配符查询，regexp和范围查询的方法。下面示例中，我对“search algorithm”执行了模糊查询，其中一本书的作者是“grant ingersoll” 或 “tom morton”，我对所有字段都进行查询，但在summary字段，boost值设为“2”。

POST /bookdb_index/book/_search

{

    "query": {

        "query_string" : {

            "query": "(saerch~1 algorithm~1) AND (grant ingersoll)  OR (tom morton)",

            "fields": ["_all", "summary^2"]

        }

    },

    "_source": [ "title", "summary", "authors" ],

    "highlight": {

        "fields" : {

            "summary" : {}

        }

    }

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "2",

        "_score": 0.14558059,

        "_source": {

          "summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",

          "title": "Taming Text: How to Find, Organize, and Manipulate It",

          "authors": [

            "grant ingersoll",

            "thomas morton",

            "drew farris"

          ]

        },

        "highlight": {

          "summary": [

            "organize text using approaches such as full-text <em>search</em>, proper name recognition, clustering, tagging, information extraction, and summarization"

          ]

        }

      }

简单查询字符串查询

简单查询字符串（simple_query_string）查询是字符串（query_string）查询的一个版本，更适合用户在单个搜索框中使用。它分别用+ / | / - 替换AND / OR / NOT的使用，并且自动过滤掉查询的无效部分，而不是在用户犯错误时抛出异常。

POST /bookdb_index/book/_search

{

    "query": {

        "simple_query_string" : {

            "query": "(saerch~1 algorithm~1) + (grant ingersoll)  | (tom morton)",

            "fields": ["_all", "summary^2"]

        }

    },

    "_source": [ "title", "summary", "authors" ],

    "highlight": {

        "fields" : {

            "summary" : {}

        }

    }

}

术语查询

以上都是全文搜索的例子。但是有些盆友对结构化搜索更感兴趣，希望在其中找到完全匹配并返回结果。这时，术语查询便可以帮到我们。在下面例子中，我们将搜索Manning Publications出版的所有书籍。

POST /bookdb_index/book/_search

{

    "query": {

        "term" : {

            "publisher": "manning"

        }

    },

    "_source" : ["title","publish_date","publisher"]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "2",

        "_score": 1.2231436,

        "_source": {

          "publisher": "manning",

          "title": "Taming Text: How to Find, Organize, and Manipulate It",

          "publish_date": "2013-01-24"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 1.2231436,

        "_source": {

          "publisher": "manning",

          "title": "Elasticsearch in Action",

          "publish_date": "2015-12-03"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 1.2231436,

        "_source": {

          "publisher": "manning",

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        }

      }

    ]

可以使用术语关键字来指定多个术语，并传入搜索术语数组。

{

    "query": {

        "terms" : {

            "publisher": ["oreilly", "packt"]

        }

    }

}

术语查询——排序

术语查询结果（与所有其他查询结果一样）可以轻松排序， 也允许多级排序：

POST /bookdb_index/book/_search

{

    "query": {

        "term" : {

            "publisher": "manning"

        }

    },

    "_source" : ["title","publish_date","publisher"],

    "sort": [

        { "publish_date": {"order":"desc"}},

        { "title": { "order": "desc" }}

    ]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": null,

        "_source": {

          "publisher": "manning",

          "title": "Elasticsearch in Action",

          "publish_date": "2015-12-03"

        },

        "sort": [

          1449100800000,

          "in"

        ]

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": null,

        "_source": {

          "publisher": "manning",

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        },

        "sort": [

          1396656000000,

          "solr"

        ]

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "2",

        "_score": null,

        "_source": {

          "publisher": "manning",

          "title": "Taming Text: How to Find, Organize, and Manipulate It",

          "publish_date": "2013-01-24"

        },

        "sort": [

          1358985600000,

          "to"

        ]

      }

    ]

范围查询

另一个结构化查询示例是范围查询。 在此示例中，我们将搜索在2015年出版的图书：

POST /bookdb_index/book/_search

{

    "query": {

        "range" : {

            "publish_date": {

                "gte": "2015-01-01",

                "lte": "2015-12-31"

            }

        }

    },

    "_source" : ["title","publish_date","publisher"]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 1,

        "_source": {

          "publisher": "oreilly",

          "title": "Elasticsearch: The Definitive Guide",

          "publish_date": "2015-02-07"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 1,

        "_source": {

          "publisher": "manning",

          "title": "Elasticsearch in Action",

          "publish_date": "2015-12-03"

        }

      }

    ]

注：范围查询适用于日期，数字和字符串类型字段。

过滤查询

过滤查询允许您过滤查询的结果。 例如，我们要查询标题或摘要中包含术语“Elasticsearch”的书籍，但要求结果过滤到包含20条以上评论的书。

POST /bookdb_index/book/_search

{

    "query": {

        "filtered": {

            "query" : {

                "multi_match": {

                    "query": "elasticsearch",

                    "fields": ["title","summary"]

                }

            },

            "filter": {

                "range" : {

                    "num_reviews": {

                        "gte": 20

                    }

                }

            }

        }

    },

    "_source" : ["title","summary","publisher", "num_reviews"]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.5955761,

        "_source": {

          "summary": "A distibuted real-time search and analytics engine",

          "publisher": "oreilly",

          "num_reviews": 20,

          "title": "Elasticsearch: The Definitive Guide"

        }

      }

    ]

注：过滤查询不要求过滤的查询的存在。如果没有指定查询，则运行match_all查询，它基本上能返回索引中的所有文档，然后对其进行过滤。 实际上，首先运行的是过滤器，这减少了需要查询的面积。 此外，过滤器在第一次使用后缓存，这能使它更高效。

POST /bookdb_index/book/_search

{

    "query": {

        "bool": {

            "must" : {

                "multi_match": {

                    "query": "elasticsearch",

                    "fields": ["title","summary"]

                }

            },

            "filter": {

                "range" : {

                    "num_reviews": {

                        "gte": 20

                    }

                }

            }

        }

    },

    "_source" : ["title","summary","publisher", "num_reviews"]

}

这同样适用于下面示例中的过滤器。

多项过滤器

多项过滤器可以通过bool过滤器结合起来，在下一个示例中，过滤器指定返回的结果必须至少有20条评论，发布时间在2015年之后，并应由oreilly发布。

POST /bookdb_index/book/_search

{

    "query": {

        "filtered": {

            "query" : {

                "multi_match": {

                    "query": "elasticsearch",

                    "fields": ["title","summary"]

                }

            },

            "filter": {

                "bool": {

                    "must": {

                        "range" : { "num_reviews": { "gte": 20 } }

                    },

                    "must_not": {

                        "range" : { "publish_date": { "lte": "2014-12-31" } }

                    },

                    "should": {

                        "term": { "publisher": "oreilly" }

                    }

                }

            }

        }

    },

    "_source" : ["title","summary","publisher", "num_reviews", "publish_date"]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.5955761,

        "_source": {

          "summary": "A distibuted real-time search and analytics engine",

          "publisher": "oreilly",

          "num_reviews": 20,

          "title": "Elasticsearch: The Definitive Guide",

          "publish_date": "2015-02-07"

        }

      }

    ]

函数权重：字段值要素

可能有这样的情况，您希望将文档中特定字段的值考虑到相关性权重的计算中。 这在脚本中很常见，基于其受欢迎程度，你会希望boost文档的相关性。 在我们的例子中，我们希望更受欢迎的书（根据评论的数量判断）得到boost。 这就可能使用到field_value_factor函数权重：

POST /bookdb_index/book/_search

{

    "query": {

        "function_score": {

            "query": {

                "multi_match" : {

                    "query" : "search engine",

                    "fields": ["title", "summary"]

                }

            },

            "field_value_factor": {

                "field" : "num_reviews",

                "modifier": "log1p",

                "factor" : 2

            }

        }

    },

    "_source": ["title", "summary", "publish_date", "num_reviews"]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.44831306,

        "_source": {

          "summary": "A distibuted real-time search and analytics engine",

          "num_reviews": 20,

          "title": "Elasticsearch: The Definitive Guide",

          "publish_date": "2015-02-07"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.3718407,

        "_source": {

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "num_reviews": 23,

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 0.046479136,

        "_source": {

          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",

          "num_reviews": 18,

          "title": "Elasticsearch in Action",

          "publish_date": "2015-12-03"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "2",

        "_score": 0.041432835,

        "_source": {

          "summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",

          "num_reviews": 12,

          "title": "Taming Text: How to Find, Organize, and Manipulate It",

          "publish_date": "2013-01-24"

        }

      }

    ]

注1：我们可以只运行一个常规的multi_match查询并按num_reviews字段排序，但是我们失去了获得相关性分值的好处。

注2：有许多额外的参数在原始相关性权重上增强boost的程度，比如“modifier”， “factor”，“boost_mode”等。这些在 Elasticsearch指南 中进行了详细探讨。

函数权重：关联功能递减函数

假设想要的不是让某个字段值按某种关联度递增，而是想让你关注的值按照同关联度递减。 这在基于lat / long，数字字段（如价格或日期）的boost中非常有用。 在下列示例中，我们要在“搜索引擎”上搜索于2014年6月发布的书籍。

POST /bookdb_index/book/_search

{

    "query": {

        "function_score": {

            "query": {

                "multi_match" : {

                    "query" : "search engine",

                    "fields": ["title", "summary"]

                }

            },

            "functions": [

                {

                    "exp": {

                        "publish_date" : {

                            "origin": "2014-06-15",

                            "offset": "7d",

                            "scale" : "30d"

                        }

                    }

                }

            ],

            "boost_mode" : "replace"

        }

    },

    "_source": ["title", "summary", "publish_date", "num_reviews"]

}

[Results]

"hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.27420625,

        "_source": {

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "num_reviews": 23,

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.005920768,

        "_source": {

          "summary": "A distibuted real-time search and analytics engine",

          "num_reviews": 20,

          "title": "Elasticsearch: The Definitive Guide",

          "publish_date": "2015-02-07"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "2",

        "_score": 0.000011564,

        "_source": {

          "summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",

          "num_reviews": 12,

          "title": "Taming Text: How to Find, Organize, and Manipulate It",

          "publish_date": "2013-01-24"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 0.0000059171475,

        "_source": {

          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",

          "num_reviews": 18,

          "title": "Elasticsearch in Action",

          "publish_date": "2015-12-03"

        }

      }

    ]

函数权重: 脚本权重

在内置评分函数不能满足您的需要的情况下，可以选择指定一个Groovy脚本用于评分。在我们的示例中，我们想要指定一个考虑发布日期的脚本，然后再决定评论数，因为新出版的书可能没有足够的评论数。

权重脚本如下所示：

publish_date = doc['publish_date'].value

num_reviews = doc['num_reviews'].value

if (publish_date > Date.parse('yyyy-MM-dd', threshold).getTime()) {

  my_score = Math.log(2.5 + num_reviews)

} else {

  my_score = Math.log(1 + num_reviews)

}

return my_score

要想动态使用权重脚本，我们需要使用脚本权重参数：

POST /bookdb_index/book/_search

{

    "query": {

        "function_score": {

            "query": {

                "multi_match" : {

                    "query" : "search engine",

                    "fields": ["title", "summary"]

                }

            },

            "functions": [

                {

                    "script_score": {

                        "params" : {

                            "threshold": "2015-07-30"

                        },

                        "script": "publish_date = doc['publish_date'].value; num_reviews = doc['num_reviews'].value; if (publish_date > Date.parse('yyyy-MM-dd', threshold).getTime()) { return log(2.5 + num_reviews) }; return log(1 + num_reviews);"

                    }

                }

            ]

        }

    },

    "_source": ["title", "summary", "publish_date", "num_reviews"]

}

[Results]

"hits": {

    "total": 4,

    "max_score": 0.8463001,

    "hits": [

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "1",

        "_score": 0.8463001,

        "_source": {

          "summary": "A distibuted real-time search and analytics engine",

          "num_reviews": 20,

          "title": "Elasticsearch: The Definitive Guide",

          "publish_date": "2015-02-07"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "4",

        "_score": 0.7067348,

        "_source": {

          "summary": "Comprehensive guide to implementing a scalable search engine using Apache Solr",

          "num_reviews": 23,

          "title": "Solr in Action",

          "publish_date": "2014-04-05"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "3",

        "_score": 0.08952084,

        "_source": {

          "summary": "build scalable search applications using Elasticsearch without having to do complex low-level programming or understand advanced data science algorithms",

          "num_reviews": 18,

          "title": "Elasticsearch in Action",

          "publish_date": "2015-12-03"

        }

      },

      {

        "_index": "bookdb_index",

        "_type": "book",

        "_id": "2",

        "_score": 0.07602123,

        "_source": {

          "summary": "organize text using approaches such as full-text search, proper name recognition, clustering, tagging, information extraction, and summarization",

          "num_reviews": 12,

          "title": "Taming Text: How to Find, Organize, and Manipulate It",

          "publish_date": "2013-01-24"

        }

      }

    ]

  }

注1：要使用动态脚本，必须在config / elasticsearch.yaml文件的Elasticsearch实例中激活。 当然，我们也可以使用存储在Elasticsearch服务器上的脚本。 更多相关信息，请参阅 Elasticsearch参考文档 。

注2：JSON不能包含嵌入的换行符，因此分号用来分隔语句。