7.6 官方文档

nested 查询

es 默认会把字段拍平, 举个栗子，比如下面这样的数据：

PUT book/_doc/1
{
  "title": "elasticsearch入门",
  "author": [
    {
      "first_name": "Andy", "last_name": "William"
    },
    {
      "first_name": "Jack", "last_name": "Smith"
    }
  ]
}

如果我们查找 Andy Smith 写的书

GET book/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "author.first_name": "Andy"
          }
        },
        {
          "match": {
            "author.last_name": "Smith"
          }
        }
      ]
    }
  }
}

返回的结果

{
  "took" : 10,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 0.5753642,
    "hits" : [
      {
        "_index" : "book",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 0.5753642,
        "_source" : {
          "title" : "elasticsearch入门",
          "author" : [
            {
              "first_name" : "Andy",
              "last_name" : "William"
            },
            {
              "first_name" : "Jack",
              "last_name" : "Smith"
            }
          ]
        }
      }
    ]
  }
}

显然是不对的，first_name 和 last_name 应该是绑定在一起的属性，所以就需要定义 nested 属性

PUT book
{
  "mappings" : {
    "properties" : {
      "author" : {
        "type": "nested", 
        "properties" : {
          "first_name" : {
            "type" : "keyword"
          },
          "last_name" : {
            "type" : "keyword"
          }
        }
      },
      "title" : {
        "type" : "text",
        "fields" : {
          "keyword" : {
            "type" : "keyword",
            "ignore_above" : 256
          }
        }
      }
    }
  }
}

查询的语句也有变化

GET book/_search
{
  "query": {
    "bool": {
      "must": {
        "nested": {
          "path": "author",
          "query": {
            "bool": {
              "must": [
                { "match": { "author.first_name": "Andy" } },
                { "match": { "author.last_name": "William" } }
              ]
            }
          }
        }
      }
    }
  }
}

这样就对了