Elasticsearch Search API

秒速五厘米 2023-01-14 01:51 170阅读 0赞

当执行一个搜索时，它将这个搜索请求**广播给所有的索引分片**。可以通过提供路由参数来控制要搜索哪些分片。例如，当检索tweets这个索引时，路由参数可以设置为用户名：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X POST "localhost:9200/twitter/_search?routing=kimchy" -H 'Content-Type: application/json' -d'
    {
        "query": {
            "bool" : {
                "must" : {
                    "query_string" : {
                        "query" : "some query string here"
                    }
                },
                "filter" : {
                    "term" : { "user" : "kimchy" }
                }
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

1.  Search

查询可以提供一个简单的查询字符串作为参数，也可以用一个请求体。

1.1.  URI Search

这种方式用的很少，就不细说了，举个例子吧：

curl -X GET "localhost:9200/product/_search?q=category:honor&sort=price:asc"

1.2.  Request Body Search

同样，举个例子：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/twitter/_search" -H 'Content-Type: application/json' -d'
    {
        "query" : {
            "term" : { "user" : "kimchy" }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

1.2.1.  Query

可以用 Query DSL 定义一个query

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
        "query" : {
            "term" : { "user" : "kimchy" }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

1.2.2.  From / Size

通过 from 和 size 参数，可以分页查询。from 表示从第几条开始取，size 表示最多取多少条。from默认值是0，size默认值是10

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "from" : 0, 
        "size" : 10,
        "query" : {
            "term" : { "user" : "kimchy" }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

1.2.3.  Sort

可以按一个或多个字段排序

有一些特殊的排序字段：\_score 表示按分数排序，\_doc 表示按索引顺序排序

假设有这样一个索引：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X PUT "localhost:9200/my_index" -H 'Content-Type: application/json' -d'
    {
        "mappings": {
            "_doc": {
                "properties": {
                    "post_date": { "type": "date" },
                    "user": {
                        "type": "keyword"
                    },
                    "name": {
                        "type": "keyword"
                    },
                    "age": { "type": "integer" }
                }
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

针对这个索引，我们这样来查询：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/my_index/_search" -H 'Content-Type: application/json' -d'
    {
        "sort" : [
            { "post_date" : {"order" : "asc"}},
            "user",
            { "name" : "desc" },
            { "age" : "desc" },
            "_score"
        ],
        "query" : {
            "term" : { "user" : "kimchy" }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

这个例子，依次按照 post\_date升序、user升序、name降序、age降序、分数升序排序

（PS：\_doc是最有效的排序，如果不关心文档的返回顺序的话）

Elasticsearch支持按数组或者多值字段排序，mode选项用来控制基于数组中的那个值来对文档进行排序。mode选项的可选值有：

*  min ：最小值
 *  max ：最大值
 *  sum ：用所有值的和来作为排序值
 *  avg ：用所有值的平均值作为排序值
 *  median ：用所有值的中间值作为排序值

举个例子：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X PUT "localhost:9200/my_index/_doc/1?refresh" -H 'Content-Type: application/json' -d'
    {
       "product": "chocolate",
       "price": [20, 4]
    }
    '
    curl -X POST "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
       "query" : {
          "term" : { "product" : "chocolate" }
       },
       "sort" : [
          {"price" : {"order" : "asc", "mode" : "avg"}}
       ]
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

什么意思呢？也就说，字段的值可能是一个数组，或者该字段值有多个，那么当我们按这种字段排序的时候就必须确定在排序的时候这个字段的值是什么，也就是该字段的排序值

所谓的mode选项就是用来确定这种字段的最终排序值的，比如：取字段值数组中最小的那个值作为该字段的排序值，或者取最大、或者平均值等等

上面的例子中，price字段值是一个数组，数组有两个元素，后面的查询指定的mode是avg，意味着price字段在排序的时候它的排序值是 (20+4)/2=12

上例中，对结果集按price字段升序排序，price字段的排序值是price字段值求平均

**Mission**

mission 参数用于指定当文档没有这个字段时该如何处理，可选值是：\_last 和 \_first ，默认是 \_last

类似于关系型数据库中字段为NULL的记录都放在最后

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
        "sort" : [
            { "price" : {"missing" : "_last"} }
        ],
        "query" : {
            "term" : { "product" : "chocolate" }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

1.2.4.  Source filtering

可以控制 \_source 字段怎样返回

默认返回 \_source字段的内容，当然你可以设置不返回该字段，例如：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
        "_source": false,
        "query" : {
            "term" : { "user" : "kimchy" }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

正常情况下，返回是这样的：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

{
            "_index" : "product",
            "_type" : "_doc",
            "_id" : "3",
            "_score" : 1.0,
            "_source" : {
              "productName" : "Honor Note10",
              "category" : "Honor",
              "price" : 2499
            }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

禁用后是这样的：

{
            "_index" : "product",
            "_type" : "_doc",
            "_id" : "3",
            "_score" : 1.0
    }

还可以用通配符，以进一步控制\_source中返回那些字段：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/product/_search?pretty" -H 'Content-Type: application/json' -d'
    {
        "_source": "product*",
        "query" : {
            "match_all" : {}
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

或者

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/product/_search?pretty" -H 'Content-Type: application/json' -d'
    {
        "_source": ["product*", "abc*"],
        "query" : {
            "match_all" : {}
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

1.2.5.  高亮

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/product/_search?pretty" -H 'Content-Type: application/json' -d'
    {
        "query" : {
            "match" : { "category" : "MI" }
        },
        "highlight" : {
            "fields" : {
                "productName": {}
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

[https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-highlighting.html][https_www.elastic.co_guide_en_elasticsearch_reference_current_search-request-highlighting.html]

1.2.6.  Explain

执行计划可以看到分数是怎样计算出来的

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
        "explain": true,
        "query" : {
            "term" : { "user" : "kimchy" }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

1.3.  Count

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/product/_doc/_count?pretty&q=category:honor"
    
    curl -X GET "localhost:9200/product/_doc/_count?pretty" -H 'Content-Type: application/json' -d'
    {
        "query" : {
            "term" : { "category" : "honor" }
        }
    }
    '
    
    {
      "count" : 3,
      "_shards" : {
        "total" : 5,
        "successful" : 5,
        "skipped" : 0,
        "failed" : 0
      }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

2.  Aggregations

相当于关系型数据库中的聚集函数（或者叫聚合函数）

**聚合可以嵌套！****聚合可以嵌套！！****聚合可以嵌套！！！**

聚合主要有4种类型：

*  Bucketing
 *  Mertric
 *  Matrix
 *  Pipeline

基本的聚合结构是这样的：

![9e41092a6bbb9e91cdd5febf321f57aa.png][]

**aggregations** 是一个JSON对象，它代表一个聚合。（PS：这个关键字也可以用 **aggs** )

1.  每个聚合都关联了一个逻辑名称（例如：如果聚合计算平均价格，那么在这个场景下我可以给这个聚合起个名字叫“avg\_price”）
2.  在响应结果中，这些逻辑名称用于唯一标识一个聚合
3.  每个聚合都有一个指定的类型（比如：sum ，avg ，max ，min 等等）
4.  每个聚合类型都定义了自己的body

2.1.  Metrics Aggregations

这种类型的聚合是基于以某种方式从聚合的文档中提取的值来计算度量。这个值通常取自文档的字段值，也可以通过脚本计算得到的。

数值度量聚合是一种特殊的度量聚合，它输出数值。根据输出值的多少，分为单值数值度量聚合（比如：avg）和多值数值度量聚合（比如：stats）。

2.1.1.  Avg

从文档的**数值字段**中提取值进行计算

假设，我们的文档是学生成绩（0~100），我们可以求平均分数：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X POST "localhost:9200/exams/_search?size=0" -H 'Content-Type: application/json' -d'
    {
        "aggs":{
            "avg_grade":{
                "avg":{
                    "field":"grade"
                }
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

上面的聚合例子，计算所有学生的平均成绩。这里的聚合类型是avg，field指定哪个字段用于计算。

再来一个例子：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X POST "localhost:9200/product/_search?size=0" -H 'Content-Type: application/json' -d'
    {
        "aggs":{
            "avg_price":{
                "avg":{
                    "field":"price"
                }
            }
        }
    }
    '
    
    响应：
    {
        "took":13,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":7,
            "max_score":0,
            "hits":[
    
            ]
        },
        "aggregations":{
            "avg_price":{
                "value":2341.5714285714284
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

默认情况下，没有那个字段的文档将被忽略（PS：就像关系型数据库中求平均值时会忽略NULL的记录一样），我们可以给它指定一个值，例如：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X POST "localhost:9200/exams/_search?size=0" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "grade_avg" : {
                "avg" : {
                    "field" : "grade",
                    "missing": 10 
                }
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

如果文档没有grade字段，那么用10作为该字段值参与计算

2.1.2.  Sum

从文档的**数值字段**中提取值进行计算

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X POST "localhost:9200/product/_search?size=0" -H 'Content-Type: application/json' -d'
    {
        "query":{
            "constant_score":{
                "filter":{
                    "match":{
                        "category":"vivo"
                    }
                }
            }
        },
        "aggs":{
            "vivo_prices":{
                "sum":{
                    "field":"price"
                }
            }
        }
    }
    '
    
    响应：
    {
        "took":3,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":2,
            "max_score":0,
            "hits":[
    
            ]
        },
        "aggregations":{
            "vivo_prices":{
                "value":3796
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

求category字段值匹配vivo的商品的价格总和

相当于，select sum(price) from product where category like '%vivo%' group by category

2.1.3.  Max

从文档的**数值字段**中提取值进行计算

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X POST "localhost:9200/sales/_search?size=0" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "max_price" : { 
                "max" : { 
                    "field" : "price" 
                } 
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

2.1.4.  Stats

这是一个多值聚合，它返回 min ，max ，sum ，count ，avg 的组合结果

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X POST "localhost:9200/exams/_search?size=0" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "grades_stats" : { 
                "stats" : { 
                    "field" : "grade" 
                } 
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

它的返回可能是这样的：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

{
        ...
    
        "aggregations": {
            "grades_stats": {
                "count": 2,
                "min": 50.0,
                "max": 100.0,
                "avg": 75.0,
                "sum": 150.0
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

再来一个例子：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X POST "localhost:9200/product/_search?size=0" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "product_stats" : { 
                "stats" : { 
                    "field" : "price" 
                } 
            }
        }
    }
    '
    
    响应：
    {
        "took":4,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":7,
            "max_score":0,
            "hits":[
    
            ]
        },
        "aggregations":{
            "product_stats":{
                "count":7,
                "min":998,
                "max":4299,
                "avg":2341.5714285714284,
                "sum":16391
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

2.2.  Bucket Aggregations

可以理解为范围聚合，它的结果是一段一段的，一个一个的bucket

2.2.1.  Range

每个Range包含from，不包含to

**前闭后开区间**

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "price_ranges" : {
                "range" : {
                    "field" : "price",
                    "ranges" : [
                        { "to" : 100.0 },
                        { "from" : 100.0, "to" : 200.0 },
                        { "from" : 200.0 }
                    ]
                }
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

返回可能是这样的：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

{
        ...
        "aggregations": {
            "price_ranges" : {
                "buckets": [
                    {
                        "key": "*-100.0",
                        "to": 100.0,
                        "doc_count": 2
                    },
                    {
                        "key": "100.0-200.0",
                        "from": 100.0,
                        "to": 200.0,
                        "doc_count": 2
                    },
                    {
                        "key": "200.0-*",
                        "from": 200.0,
                        "doc_count": 3
                    }
                ]
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

再比如：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X GET "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "price_ranges" : {
                "range" : {
                    "field" : "price",
                    "ranges" : [
                        { "to" : 1000 },
                        { "from" : 1000, "to" : 2000 },
                        { "from" : 2000 }
                    ]
                }
            }
        }
    }
    '
    
    响应：
    {
        "took":1,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":7,
            "max_score":1,
            "hits":[
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"5",
                    "_score":1,
                    "_source":{
                        "productName":"MI 8",
                        "category":"MI",
                        "price":2499
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"2",
                    "_score":1,
                    "_source":{
                        "productName":"Honor Magic2",
                        "category":"Honor",
                        "price":4299
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"4",
                    "_score":1,
                    "_source":{
                        "productName":"MI Max2",
                        "category":"MI",
                        "price":1099
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"6",
                    "_score":1,
                    "_source":{
                        "productName":"vivo X23",
                        "category":"vivo",
                        "price":2798
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"1",
                    "_score":1,
                    "_source":{
                        "productName":"Honor 10",
                        "category":"Honor",
                        "price":2199
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"7",
                    "_score":1,
                    "_source":{
                        "productName":"vivo Z1",
                        "category":"vivo",
                        "price":998
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"3",
                    "_score":1,
                    "_source":{
                        "productName":"Honor Note10",
                        "category":"Honor",
                        "price":2499
                    }
                }
            ]
        },
        "aggregations":{
            "price_ranges":{
                "buckets":[
                    {
                        "key":"*-1000.0",
                        "to":1000,
                        "doc_count":1
                    },
                    {
                        "key":"1000.0-2000.0",
                        "from":1000,
                        "to":2000,
                        "doc_count":1
                    },
                    {
                        "key":"2000.0-*",
                        "from":2000,
                        "doc_count":5
                    }
                ]
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

代替返回一个数组，可以设置keyed为true，这样可以给每个bucket关联一个位于的字符串key，例如：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "price_ranges" : {
                "range" : {
                    "field" : "price",
                    "keyed" : true,
                    "ranges" : [
                        { "to" : 100 },
                        { "from" : 100, "to" : 200 },
                        { "from" : 200 }
                    ]
                }
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

于是返回变成这样了：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

{
        ...
        "aggregations": {
            "price_ranges" : {
                "buckets": {
                    "*-100.0": {
                        "to": 100.0,
                        "doc_count": 2
                    },
                    "100.0-200.0": {
                        "from": 100.0,
                        "to": 200.0,
                        "doc_count": 2
                    },
                    "200.0-*": {
                        "from": 200.0,
                        "doc_count": 3
                    }
                }
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

当然，我们也可以给每个范围区间自定义key：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "price_ranges" : {
                "range" : {
                    "field" : "price",
                    "keyed" : true,
                    "ranges" : [
                        { "key" : "cheap", "to" : 100 },
                        { "key" : "average", "from" : 100, "to" : 200 },
                        { "key" : "expensive", "from" : 200 }
                    ]
                }
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

{
        ...
        "aggregations": {
            "price_ranges" : {
                "buckets": {
                    "cheap": {
                        "to": 100.0,
                        "doc_count": 2
                    },
                    "average": {
                        "from": 100.0,
                        "to": 200.0,
                        "doc_count": 2
                    },
                    "expensive": {
                        "from": 200.0,
                        "doc_count": 3
                    }
                }
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

举个栗子：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X GET "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "query": {
            "match" : { "category" : "honor"}
        },
        "aggs" : {
            "price_ranges" : {
                "range" : {
                    "field" : "price",
                    "keyed" : true,
                    "ranges" : [
                        { "key" : "low", "to" : 1000 },
                        { "key" : "medium", "from" : 1000, "to" : 2000 },
                        { "key" : "high", "from" : 2000 }
                    ]
                }
            }
        }
    }
    '
    
    响应：
    {
        "took":1,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":3,
            "max_score":0.9808292,
            "hits":[
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"2",
                    "_score":0.9808292,
                    "_source":{
                        "productName":"Honor Magic2",
                        "category":"Honor",
                        "price":4299
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"1",
                    "_score":0.6931472,
                    "_source":{
                        "productName":"Honor 10",
                        "category":"Honor",
                        "price":2199
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"3",
                    "_score":0.2876821,
                    "_source":{
                        "productName":"Honor Note10",
                        "category":"Honor",
                        "price":2499
                    }
                }
            ]
        },
        "aggregations":{
            "price_ranges":{
                "buckets":{
                    "low":{
                        "to":1000,
                        "doc_count":0
                    },
                    "medium":{
                        "from":1000,
                        "to":2000,
                        "doc_count":0
                    },
                    "high":{
                        "from":2000,
                        "doc_count":3
                    }
                }
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

2.2.2.  Filter

先过滤再聚合

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X POST "localhost:9200/product/_search?size=0" -H 'Content-Type: application/json' -d'
    {
        "aggs":{
            "vivo":{
                "filter":{
                    "term":{
                        "category":"vivo"
                    }
                },
                "aggs":{
                    "avg_price":{
                        "avg":{
                            "field":"price"
                        }
                    }
                }
            }
        }
    }
    '
    
    响应：
    {
        "took":2,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":7,
            "max_score":0,
            "hits":[
    
            ]
        },
        "aggregations":{
            "vivo":{
                "doc_count":2,
                "avg_price":{
                    "value":1898
                }
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

2.2.3.  Terms Aggregation

相当于关系型数据库中的分组（group by）

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X GET "localhost:9200/_search" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "genres" : {
                "terms" : { "field" : "genre" }
            }
        }
    }
    '

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

返回可能是这样的：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

{
        ...
        "aggregations" : {
            "genres" : {
                "doc_count_error_upper_bound": 0, 
                "sum_other_doc_count": 0, 
                "buckets" : [ 
                    {
                        "key" : "electronic",
                        "doc_count" : 6
                    },
                    {
                        "key" : "rock",
                        "doc_count" : 3
                    },
                    {
                        "key" : "jazz",
                        "doc_count" : 2
                    }
                ]
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

再举个例子：

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X GET "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "group_by_category" : {
                "terms" : { "field" : "category" }
            }
        }
    }
    '
    
    响应：
    {
        "took":16,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":7,
            "max_score":1,
            "hits":[
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"5",
                    "_score":1,
                    "_source":{
                        "productName":"MI 8",
                        "category":"MI",
                        "price":2499
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"2",
                    "_score":1,
                    "_source":{
                        "productName":"Honor Magic2",
                        "category":"Honor",
                        "price":4299
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"4",
                    "_score":1,
                    "_source":{
                        "productName":"MI Max2",
                        "category":"MI",
                        "price":1099
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"6",
                    "_score":1,
                    "_source":{
                        "productName":"vivo X23",
                        "category":"vivo",
                        "price":2798
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"1",
                    "_score":1,
                    "_source":{
                        "productName":"Honor 10",
                        "category":"Honor",
                        "price":2199
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"7",
                    "_score":1,
                    "_source":{
                        "productName":"vivo Z1",
                        "category":"vivo",
                        "price":998
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"3",
                    "_score":1,
                    "_source":{
                        "productName":"Honor Note10",
                        "category":"Honor",
                        "price":2499
                    }
                }
            ]
        },
        "aggregations":{
            "group_by_category":{
                "doc_count_error_upper_bound":0,
                "sum_other_doc_count":0,
                "buckets":[
                    {
                        "key":"honor",
                        "doc_count":3
                    },
                    {
                        "key":"mi",
                        "doc_count":2
                    },
                    {
                        "key":"vivo",
                        "doc_count":2
                    }
                ]
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

size 可以用于指定返回多少个term bucket

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X GET "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "group_by_category" : {
                "terms" : { 
                    "field" : "category",
                    "size" : 2
                }
            }
        }
    }
    '
    
    响应：
    {
        ...
        
        "aggregations":{
            "group_by_category":{
                "doc_count_error_upper_bound":0,
                "sum_other_doc_count":2,
                "buckets":[
                    {
                        "key":"honor",
                        "doc_count":3
                    },
                    {
                        "key":"mi",
                        "doc_count":2
                    }
                ]
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

3.  示例

排序

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X POST "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "query" : {
            "term" : { "category" : "honor"}
        },
        "sort" : "price"
    }
    
    '
    curl -X POST "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "query" : {
            "term" : { "category" : "honor"}
        },
        "sort" : { "price" : "desc" }
    }
    '
    
    curl -X POST "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "query" : {
            "term" : { "category" : "honor"}
        },
        "sort" : { "price" : { "order" : "desc" } }
    }
    '
    
    响应：
    {
        "took":1,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":3,
            "max_score":null,
            "hits":[
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"2",
                    "_score":null,
                    "_source":{
                        "productName":"Honor Magic2",
                        "category":"Honor",
                        "price":4299
                    },
                    "sort":[
                        4299
                    ]
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"3",
                    "_score":null,
                    "_source":{
                        "productName":"Honor Note10",
                        "category":"Honor",
                        "price":2499
                    },
                    "sort":[
                        2499
                    ]
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"1",
                    "_score":null,
                    "_source":{
                        "productName":"Honor 10",
                        "category":"Honor",
                        "price":2199
                    },
                    "sort":[
                        2199
                    ]
                }
            ]
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

分组求平均

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

请求：
    curl -X GET "localhost:9200/product/_search" -H 'Content-Type: application/json' -d'
    {
        "aggs" : {
            "group_by_category" : {
                "terms" : { 
                    "field" : "category"
                },
                "aggs" : {
                    "avg_price" : {
                        "avg" : {
                            "field" : "price"
                        }
                    }
                }
            }
        }
    }
    '
    
    响应：
    {
        "took":2,
        "timed_out":false,
        "_shards":{
            "total":5,
            "successful":5,
            "skipped":0,
            "failed":0
        },
        "hits":{
            "total":7,
            "max_score":1,
            "hits":[
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"5",
                    "_score":1,
                    "_source":{
                        "productName":"MI 8",
                        "category":"MI",
                        "price":2499
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"2",
                    "_score":1,
                    "_source":{
                        "productName":"Honor Magic2",
                        "category":"Honor",
                        "price":4299
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"4",
                    "_score":1,
                    "_source":{
                        "productName":"MI Max2",
                        "category":"MI",
                        "price":1099
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"6",
                    "_score":1,
                    "_source":{
                        "productName":"vivo X23",
                        "category":"vivo",
                        "price":2798
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"1",
                    "_score":1,
                    "_source":{
                        "productName":"Honor 10",
                        "category":"Honor",
                        "price":2199
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"7",
                    "_score":1,
                    "_source":{
                        "productName":"vivo Z1",
                        "category":"vivo",
                        "price":998
                    }
                },
                {
                    "_index":"product",
                    "_type":"_doc",
                    "_id":"3",
                    "_score":1,
                    "_source":{
                        "productName":"Honor Note10",
                        "category":"Honor",
                        "price":2499
                    }
                }
            ]
        },
        "aggregations":{
            "group_by_category":{
                "doc_count_error_upper_bound":0,
                "sum_other_doc_count":0,
                "buckets":[
                    {
                        "key":"honor",
                        "doc_count":3,
                        "avg_price":{
                            "value":2999
                        }
                    },
                    {
                        "key":"mi",
                        "doc_count":2,
                        "avg_price":{
                            "value":1799
                        }
                    },
                    {
                        "key":"vivo",
                        "doc_count":2,
                        "avg_price":{
                            "value":1898
                        }
                    }
                ]
            }
        }
    }

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

4.  示例索引

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

curl -X PUT "localhost:9200/product" -H 'Content-Type: application/json' -d'
    {
        "mappings" : {
            "_doc" : {
                "properties": {
                    "productName": {"type": "text"},
                    "category": {"type": "text", "fielddata": true},
                    "price": {"type": "integer"}
                }
            }
        }
    }
    '
    
    curl -X POST "localhost:9200/product/_doc/_bulk" -H 'Content-Type: application/json' --data-binary "@product.json"
    
    
    {"index" : {"_id" : "1" } }
    {"productName" : "Honor 10", "category" : "Honor", "price" : 2199}
    {"index" : {"_id" : "2" } }
    {"productName" : "Honor Magic2", "category" : "Honor", "price" : 4299}
    {"index" : {"_id" : "3" } }
    {"productName" : "Honor Note10", "category" : "Honor", "price" : 2499}
    {"index" : {"_id" : "4" } }
    {"productName" : "MI Max2", "category" : "MI", "price" : 1099}
    {"index" : {"_id" : "5" } }
    {"productName" : "MI 8", "category" : "MI", "price" : 2499}
    {"index" : {"_id" : "6" } }
    {"productName" : "vivo X23", "category" : "vivo", "price" : 2798}
    {"index" : {"_id" : "7" } }
    {"productName" : "vivo Z1", "category" : "vivo", "price" : 998}

![复制代码][48304ba5e6f9fe08f3fa1abda7d326ab.png]

5.  参考

[https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-metrics.html][https_www.elastic.co_guide_en_elasticsearch_reference_current_search-aggregations-metrics.html]

[https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket.html][https_www.elastic.co_guide_en_elasticsearch_reference_current_search-aggregations-bucket.html]

6.  其它相关

《[Elasticsearch查询][Elasticsearch]》

[48304ba5e6f9fe08f3fa1abda7d326ab.png]: /images/20221022/fa1eb69adbe34222b772773488b6019f.png
[https_www.elastic.co_guide_en_elasticsearch_reference_current_search-request-highlighting.html]: https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-highlighting.html
[9e41092a6bbb9e91cdd5febf321f57aa.png]: /images/20221022/984f45232b144cfe82c9669bd224b645.png
[https_www.elastic.co_guide_en_elasticsearch_reference_current_search-aggregations-metrics.html]: https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-metrics.html
[https_www.elastic.co_guide_en_elasticsearch_reference_current_search-aggregations-bucket.html]: https://www.elastic.co/guide/en/elasticsearch/reference/current/search-aggregations-bucket.html
[Elasticsearch]: https://www.cnblogs.com/cjsblog/p/9910788.html