Introduction > Query II > 嵌套类型的查询

嵌套类型的查询

在第三章我们介绍了嵌套类型。由于嵌套对象被索引在独立隐藏的文档中，我们无法直接查询它们。相应地，我们必须使用 nested查询去获取它们。

嵌套类型查询测试

创建一个索引department，它的employees字段是nested类型：

PUT /department
{
  "mappings": {  
    "properties": {
      "name": {
        "type": "text"
      },
      "employees": {
        "type": "nested"
      }
    }
  }
}

往里面插入两条文档：

PUT /department/_doc/1
{
  "name": "Development",
  "employees": [
    {
      "name": "Eric Green",
      "age": 39,
      "gender": "M",
      "position": "Big Data Specialist"
    },
    {
      "name": "James Taylor",
      "age": 27,
      "gender": "M",
      "position": "Software Developer"
    },
    {
      "name": "Gary Jenkins",
      "age": 21,
      "gender": "M",
      "position": "Intern"
    },
    {
      "name": "Julie Powell",
      "age": 26,
      "gender": "F",
      "position": "Intern"
    },
    {
      "name": "Benjamin Smith",
      "age": 46,
      "gender": "M",
      "position": "Senior Software Engineer"
    }
  ]
}

PUT /department/_doc/2
{
  "name": "HR & Marketing",
  "employees": [
    {
      "name": "Patricia Lewis",
      "age": 42,
      "gender": "F",
      "position": "Senior Marketing Manager"
    },
    {
      "name": "Maria Anderson",
      "age": 56,
      "gender": "F",
      "position": "Head of HR"
    },
    {
      "name": "Margaret Harris",
      "age": 19,
      "gender": "F",
      "position": "Intern"
    },
    {
      "name": "Ryan Nelson",
      "age": 31,
      "gender": "M",
      "position": "Marketing Manager"
    },
    {
      "name": "Kathy Williams",
      "age": 49,
      "gender": "F",
      "position": "Senior Marketing Manager"
    },
    {
      "name": "Jacqueline Hill",
      "age": 28,
      "gender": "F",
      "position": "Junior Marketing Manager"
    },
    {
      "name": "Donald Morris",
      "age": 39,
      "gender": "M",
      "position": "SEO Specialist"
    },
    {
      "name": "Evelyn Henderson",
      "age": 24,
      "gender": "F",
      "position": "Intern"
    },
    {
      "name": "Earl Moore",
      "age": 21,
      "gender": "M",
      "position": "Junior SEO Specialist"
    },
    {
      "name": "Phillip Sanchez",
      "age": 35,
      "gender": "M",
      "position": "SEM Specialist"
    }
  ]
}

假设我们想查出position == Intern && gender == F的记录，如果使用bool查询，发现查不出结果：

GET department/_search
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "employees.position": "intern"
          }
        },
        {
          "term": {
            "employees.gender.keyword": {
              "value": "F"
            }
          }
        }
      ]
    }
  }   
}

但索引里面确实存在满足条件的记录。这是因为必须使用nested查询：

GET department/_search
{
  "query": {
    "nested": {
      "path": "employees",
      "query": {
        "bool": {
          "must": [
            {
              "match": {
                "employees.position": "intern"
              }
            },
            {
              "term": {
                "employees.gender.keyword": {
                  "value": "F"
                }
              }
            }
          ]
        }
      }   
    }
  } 
}

从返回结果中我们看到查出来position == Intern && gender == F的记录：

参考： https://www.elastic.co/guide/cn/elasticsearch/guide/current/nested-query.html