Elasticsearch学习笔记之常用的几种搜索方式

1、Query string search

由于 这种搜索方式的语法特别 像http 中的Query String 形式,所以叫做 Query string search

语法 GET /index/type/_search?param

例如想搜索 全部商品

GET /ecommerce/product/_search

{
  "took": 2,   //耗费了几毫秒
  "timed_out": false, //是否超时，这里是没有
  "_shards": { //数据拆成了5个分片，所以对于搜索请求，会打到所有的primary shard（或者是它的某个replica shard也可以）
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 4, //查询结果的数量，3个document
    "max_score": 1,  //score的含义，就是document对于一个search的相关度的匹配分数，越相关，就越匹配，分数也高
    "hits": [ //包含了匹配搜索的document的详细数据
      {
        "_index": "ecommerce",
        "_type": "product",
        "_id": "2",
        "_score": 1,
        "_source": {
          "name": "jiajieshi yagao",
          "desc": "youxiao fangzhu",
          "price": 25,
          "producer": "jiajieshi producer",
          "tags": [
            "fangzhu"
          ]
        }
      },
      {
        "_index": "ecommerce",
        "_type": "product",
        "_id": "4",
        "_score": 1,
        "_source": {
          "name": "gaolujie yagao",
          "desc": "gaoxiao meibai",
          "price": 30,
          "producer": "gaolujie producter",
          "tags": [
            "meibai",
            "fangzhu"
          ]
        }
      },
      {
        "_index": "ecommerce",
        "_type": "product",
        "_id": "1",
        "_score": 1,
        "_source": {
          "name": "gaolujie yagao",
          "desc": "gaoxiao meibai",
          "price": 30,
          "producer": "gaolujie producter",
          "tags": [
            "meibai",
            "fangzhu"
          ]
        }
      },
      {
        "_index": "ecommerce",
        "_type": "product",
        "_id": "3",
        "_score": 1,
        "_source": {
          "name": "zhonghua yagao",
          "desc": "caoben zhiwu",
          "price": 40,
          "producer": "zhonghua producer",
          "tags": [
            "qingxin"
          ]
        }
      }
    ]
  }
}

再或者想搜索商品名中包含牙膏的商品,并且按照价格降序排列

GET /ecommerce/product/_search?q=name:yagao&sort=price:desc

{
  "took": 3,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 4,
    "max_score": null,
    "hits": [
      {
        "_index": "ecommerce",
        "_type": "product",
        "_id": "3",
        "_score": null,
        "_source": {
          "name": "zhonghua yagao",
          "desc": "caoben zhiwu",
          "price": 40,
          "producer": "zhonghua producer",
          "tags": [
            "qingxin"
          ]
        },
        "sort": [
          40
        ]
      },
      {
        "_index": "ecommerce",
        "_type": "product",
        "_id": "4",
        "_score": null,
        "_source": {
          "name": "gaolujie yagao",
          "desc": "gaoxiao meibai",
          "price": 30,
          "producer": "gaolujie producter",
          "tags": [
            "meibai",
            "fangzhu"
          ]
        },
        "sort": [
          30
        ]
      },
      {
        "_index": "ecommerce",
        "_type": "product",
        "_id": "1",
        "_score": null,
        "_source": {
          "name": "gaolujie yagao",
          "desc": "gaoxiao meibai",
          "price": 30,
          "producer": "gaolujie producter",
          "tags": [
            "meibai",
            "fangzhu"
          ]
        },
        "sort": [
          30
        ]
      },
      {
        "_index": "ecommerce",
        "_type": "product",
        "_id": "2",
        "_score": null,
        "_source": {
          "name": "jiajieshi yagao",
          "desc": "youxiao fangzhu",
          "price": 25,
          "producer": "jiajieshi producer",
          "tags": [
            "fangzhu"
          ]
        },
        "sort": [
          25
        ]
      }
    ]
  }
}

此种方式适用于临时的在命令行使用一些工具，比如curl，快速的发出请求，来检索想要的信息；但是如果查询请求很复杂，是很难去构建的
在生产环境中，几乎很少使用query string search

2、Query DSL

DSL：Domain Specified Language，特定领域的语言

http request body：请求体，可以用json的格式来构建查询语法，比较方便，可以构建各种复杂的语法，比query string search肯定强大多了

语法 GET /index/type/_search
{
body param
}

例如想查询所有商品

GET /ecommerce/product/_search
{
  "query": {
    "match_all": {
    }
  }
}

查询名称包含yagao的商品，同时按照价格降序排序

GET /ecommerce/product/_search
{
  "query": {
    "match": {
      "name": "yagao" //支持全文检索
    }
  },
  "sort": [  //加了sort后 _score会丢失
    {
      "price": "desc"
    }
  ]
}

分页查询商品，总共3条商品，假设每页就显示1条商品，现在显示第2页，所以就查出来第2个商品

GET /ecommerce/product/_search
{
  "query": {
    "match_all": {}
  },
  "from": 0,
  "size": 1
}

指定要查询出来商品的列

GET /ecommerce/product/_search
{
  "query": {
    "match_all": {}
  },
  "_source": ["name","price"]
  
}

3、Query filter

搜索商品名称包含yagao，而且售价大于等于30元的商品
另外说明filter不会计算相关度评分_soure，并且会将结果进行缓存，所以其性能要好于query

GET /ecommerce/product/_search
{
  "query": {
    "bool": {
      "must": {
        "match": {
          "name": "yagao"
        } 
      }
      ,
      "filter": {
        "range": {
          "price": {
            "gte": 30
          }
        }
      }
    }
  }
}

4、Full-text search（全文检索）

GET /ecommerce/product/_search
{
    "query" : {
        "match" : {
            "producer" : "yagao producer"
        }
    }
}

5、Phrase search（短语搜索）

跟全文检索相对应，相反，全文检索会将输入的搜索串拆解开来，去倒排索引里面去一一匹配，只要能匹配上任意一个拆解后的单词，就可以作为结果返回
phrase search，要求输入的搜索串，必须在指定的字段文本中，完全包含一模一样的，才可以算匹配，才能作为结果返回

GET /ecommerce/product/_search
{
  "query": {
    "match_phrase": {
      "name": "zhonghua yagao"
    }
  }
}

6、Highlight search （高亮搜索结果）

GET /ecommerce/product/_search
{
  "query": {
    "match": {
      "name": "yagao"
    }
  },
  "highlight": {
    "fields": { 
      "name":{} 
    }
  }
  
}