Elasticsearch Search APIs

Search APIs 官方文档：https://www.elastic.co/guide/en/elasticsearch/reference/current/search.html

Search APIs

Search API 可以分成两类：URL Search 和 Request Body Search。URL Search 在 URL 中使用查询参数；Request Body Search 使用 Elasticsearch 提供的，基于 JSON 格式的更加完备的 Query Domain Specific Language(DSL)

语法	范围
_search	集群上所有索引
/index1/_search	index1
/index1,index2/_search	index1 和 index2
/index*/_search	以 index 开头的索引

在 URI Search 中，可以通过多种方式灵活地进行搜索。

/_search - 整个集群
/index1/_search - 单个索引
/index1,index2/_search - 多个索引
/index*/_search - 通配符索引

使用 q，指定查询字符串

#URI Query
GET kibana_sample_data_ecommerce/_search?q=customer_first_name:Eddie
- q 用来表示查询内容
- customer_first_name:Eddie 用来表示搜素一个叫 Eddie 的客户

GET kibana*/_search?q=customer_first_name:Eddie
GET /_all/_search?q=customer_first_name:Eddie

Request Body Query

#REQUEST Body
POST kibana_sample_data_ecommerce/_search
{
    "profile": true,
    "query": {
        "match_all": {}
    }
}
query: 查询
match_all: 返回所有的文档

took - 花费的时间

time_out - 是否超时

_shards - 分片信息

total - 总文档数

hits - 结果集，默认前10个

_index - 索引名称

_id - 文档的id

_score - 相关度分数

_source - 文档原始数据

https://searchenginewatch.com/sew/news/2065080/search-engines-101

https://www.huffpost.com/entry/search-engines-101-part-i_b_1104525

https://www.entrepreneur.com/article/176398

https://www.searchtechnologies.com/meaning-of-relevancy

URI Search

• 指定字段查询，泛查询
• 使用 Profile 参数
• Terms 查询和 Phrase 查询的区别
• 如何对查询条件分组
• 逻辑操作符
• 通配符和近似匹配

基本的查询语句如下：

GET /movies/_search?q=2012&df=title&sort=year:desc&from=0&size=10&timeout=1s
{
  "profile": "true"
}

• q 指定查询语句，使用 Query String Syntax
• df 默认字段，不指定时
• sort 排序
• from 和 size 用于分页
• profile 可以查看查询时如何被执行的
• timeout 指定超时时间，默认不超时

指定字段 vs 泛查询，即 q=title:2012 和 q=2012。

# 带profile
GET /movies/_search?q=2012&df=title
{
    "profile":"true"
}

#泛查询，正对_all,所有字段
GET /movies/_search?q=2012
{
    "profile":"true"
}

#指定字段
GET /movies/_search?q=title:2012&sort=year:desc&from=0&size=10&timeout=1s
{
    "profile":"true"
}

# 泛查询
GET /movies/_search?q=title:2012
{
    "profile":"true"
}

Term vs Phrase

• Beautiful Mind 等效于 Beautiful OR Mind
• Beautiful Mind 等效于 Beautiful AND Mind。Pharse查询还要求前后顺序保持一致

# 查找美丽心灵, Mind为泛查询
GET /movies/_search?q=title:Beautiful Mind
{
    "profile":"true"
}

#使用引号，Phrase查询
GET /movies/_search?q=title:"Beautiful Mind"
{
    "profile":"true"
}

分组与引号

• title:(Beautiful AND Mind)

• title=“Beautiful Mind”

#分组，Bool查询
GET /movies/_search?q=title:(Beautiful Mind)
{
    "profile":"true"
}

布尔操作符 AND OR NOT 或者 && || !

# 查找美丽心灵
GET /movies/_search?q=title:(Beautiful AND Mind)
{
    "profile":"true"
}

# 查找美丽心灵
GET /movies/_search?q=title:(Beautiful NOT Mind)
{
    "profile":"true"
}

分组+表示 must， - 表示 must_not，title:(+matrix-reloaded)

# 查找美丽心灵
GET /movies/_search?q=title:(Beautiful +Mind)
{
    "profile":"true"
}

范围查询 ,区间写法。[]闭区间，{}开区间:year:{2019 TO 2018}, year:[* TO 2018]。

算术符号year:>2010,year:(>2010 && <=2018),year:(+>2010 +<=2018)。

GET /movies/_search?q=title:beautiful AND year:[2002 TO 2018)
{
    "profile":"true"
}

# 通配符查询
- 通配符查询效率低，占用内存大，不建议使用，特别是放在最前面的时候
- ? 表示 1 个字符，* 代表 0 或多个字符
- title:mi?d
- title:be*

GET /movies/_search?q=title:b*
{
    "profile":"true"
}


# 正则表达式


# 模糊匹配&近似度匹配
title:befutifl~1
title:"lord rings"~2

GET /movies/_search?q=title:beautifl~1
{
    "profile":"true"
}


GET /movies/_search?q=title:"Lord Rings"~2
{
    "profile":"true"
}

https://www.elastic.co/guide/en/elasticsearch/reference/7.0/search-uri-request.html

https://www.elastic.co/guide/en/elasticsearch/reference/7.0/search-search.html

https://www.jianshu.com/p/8fa06643a682

Request Body Search

• 分页 / 排序
• Source Filtering
• Match 查询和 Match Phrase 查询
• 调整 Precision & Recall

# 新增一批数据
POST _bulk
{"index":{ "_index": "books", "_type": "IT", "_id": "1" }}
{"id":"1","title":"Java编程思想","language":"java","author":"Bruce Eckel","price":70.20,"publish_time":"2007-10-01","description":"Java学习必读经典,殿堂级著作！赢得了全球程序员的广泛赞誉。"}
{"index":{ "_index": "books", "_type": "IT", "_id": "2" }}
{"id":"2","title":"Java程序性能优化","language":"java","author":"葛一鸣","price":46.50,"publish_time":"2012-08-01","description":"让你的Java程序更快、更稳定。深入剖析软件设计层面、代码层面、JVM虚拟机层面的优化方法"}
{"index":{ "_index": "books", "_type": "IT", "_id": "3" }}
{"id":"3","title":"Python科学计算","language":"python","author":"张若愚","price":81.40,"publish_time":"2016-05-01","description":"零基础学python,光盘中作者独家整合开发winPython运行环境，涵盖了Python各个扩展库"}
{"index":{ "_index": "books", "_type": "IT", "_id": "4" }}
{"id":"4","title":"Python基础教程","language":"python","author":"Helant","price":54.50,"publish_time":"2014-03-01","description":"经典的Python入门教程，层次鲜明，结构严谨，内容翔实"}
{"index":{ "_index": "books", "_type": "IT", "_id": "5" }}
{"id":"5","title":"JavaScript高级程序设计","language":"javascript","author":"Nicholas C. Zakas","price":66.40,"publish_time":"2012-10-01","description":"JavaScript技术经典名著"}

查询所有数据

GET books/_search
{
  "query": {
    "match_all": {}
  }
}

等价于

GET books/_search

Request Body Search 将查询语句通过 HTTP Request Body 发送给 Elasticsearch

Query DSL，ignore_unavailable=true，可以忽略尝试访问不存在的索引“404_idx”导致的报错

POST /movies,404_idx/_search?ignore_unavailable=true
{
  "profile": true,
  "query": {
    "match_all": {}
  }
}

分页查询

分页查询，from 从 0 开始，默认返回 10 个结果，size 指定返回结果数量：

POST /kibana_sample_data_ecommerce/_search
{
  "from":10,
  "size":20,
  "query":{
    "match_all": {}
  }
}

排序

1、最好在“数字型”和“日期型”字段上排序

2、因为对于多值类型或分析过的字段排序，系统会选一个值，无法得知该值

# 对日期排序
POST kibana_sample_data_ecommerce/_search
{
  "sort":[{"order_date":"desc"}],
  "query":{
    "match_all": {}
  }
}

source filtering

source filtering 的意思是对返回的 _source 中的内容进行过滤。如果 _source 没有存储，那就只返回匹配的文档的元数据。_source 支持使用通配符，_source["name*"]。

POST kibana_sample_data_ecommerce/_search
{
  "_source":["order_date"],
  "query":{
    "match_all": {}
  }
}

脚本字段

用例：订单中有不同的汇率，需要结合汇率对订单价格进行排序

GET kibana_sample_data_ecommerce/_search
{
  "script_fields": {
    "new_field": {
      "script": {
        "lang": "painless",
        "source": "doc['order_date'].value+'hello'"
      }
    }
  },
  "query": {
    "match_all": {}
  }
}

查询表达式 - Match

POST movies/_search
{
  "query": {
    "match": {
      "title": "last christmas"
    }
  }
}


POST movies/_search
{
  "query": {
    "match": {
      "title": {
        "query": "last christmas",
        "operator": "and"
      }
    }
  }
}

短语搜索 - Match Phrase

POST movies/_search
{
  "query": {
    "match_phrase": {
      "title":{
        "query": "one love"


      }
    }
  }
}


POST movies/_search
{
  "query": {
    "match_phrase": {
      "title":{
        "query": "one love",
        "slop": 1


      }
    }
  }
}

Query string && Simple query string

• URI Query
• Query String
• Simple Query String

POST users/_search
{
  "query": {
    "query_string": {
      "default_field": "name",
      "query": "Ruan AND Yiming"
    }
  }
}

Simple Query String 类似 Query String，但是会忽略错误的语法，同时只支持部分查询语法。

• 不支持 AND OR NOT，会当作字符串处理；
• Term 之间默认的关系是 OR，可以指定 Operator；
• 支持部分逻辑：+ 代替 AND,| 代替 OR,- 代替 NOT。

POST users/_search
{
  "query": {
    "query_string": {
      "fields":["name","about"],
      "query": "(Ruan AND Yiming) OR (Java AND Elasticsearch)"
    }
  }
}

#Simple Query 默认的operator是 Or
POST users/_search
{
  "query": {
    "simple_query_string": {
      "query": "Ruan AND Yiming",
      "fields": ["name"]
    }
  }
}

POST users/_search
{
  "query": {
    "simple_query_string": {
      "query": "Ruan Yiming",
      "fields": ["name"],
      "default_operator": "AND"
    }
  }
}

GET /movies/_search
{
  "profile": true,
  "query":{
    "query_string":{
      "default_field": "title",
      "query": "Beafiful AND Mind"
    }
  }
}

# 多fields
GET /movies/_search
{
  "profile": true,
  "query":{
    "query_string":{
      "fields":[
        "title",
        "year"
      ],
      "query": "2012"
    }
  }
}

GET /movies/_search
{
  "profile":true,
  "query":{
    "simple_query_string":{
      "query":"Beautiful +mind",
      "fields":["title"]
    }
  }
}

相关资料

https://www.elastic.co/guide/en/elasticsearch/reference/7.0/search-uri-request.html

https://www.elastic.co/guide/en/elasticsearch/reference/7.0/search-search.html

https://www.jianshu.com/p/6ba5c755fe3f