Elasticsearch 排除包含特定术语的文档

Question

我已经在elasticsearch索引了像波纹管这样的文档。

{    
    "category": "clothing (f)",
    "description": "Women's Unstoppable Graphic T-Shirt - Women’s Short Sleeve Shirt",
    "name": "Women's Unstoppable Graphic T-Shirt",
    "price": "$34.99"
}

有clothing (m) 、 clothing (f)等类别。如果搜索的是女性物品，我试图排除cloting (m)类别物品。 我正在尝试的查询是：

{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "description": "women's black shirt"
          }
        }
      ],
      "must_not": [
        {
          "term": {
            "category": "clothing (m)"
          }
        }
      ]
    }
  },
  "from": 0,
  "size": 50
}

但这并没有按预期工作。 clothing (m)文件与其他文件的结果总是很少。 如何排除具有特定类别的文档？

Answer 1

为了排除特定term （完全匹配），您必须使用keyword数据类型。

关键字数据类型通常用于过滤（查找已发布状态的所有博客文章）、排序和聚合。 关键字字段只能按其确切值进行搜索。

关键字数据类型

您当前的查询在结果中捕获了服装 (m) ，因为当您为文档编制索引时，它们会使用 elasticsearch standard分析器进行分析，该分析器将服装 (m)分析为服装和(m) 。

在您的查询中，您将category搜索为text数据类型。

文本数据类型字段被分析，也就是说，它们在被索引之前通过分析器将字符串转换为单个术语的列表。

运行此命令：

POST my_index/_analyze
{
  "text": ["clothing (m)"]
}

结果：

{
  "tokens" : [
    {
      "token" : "clothing",
      "start_offset" : 0,
      "end_offset" : 8,
      "type" : "<ALPHANUM>",
      "position" : 0
    },
    {
      "token" : "m",
      "start_offset" : 10,
      "end_offset" : 11,
      "type" : "<ALPHANUM>",
      "position" : 1
    }
  ]
}

一个工作示例：

假设您的映射如下所示：

{
 "my_index" : {
    "mappings" : {
      "properties" : {
        "category" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "description" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "name" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "price" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        }
      }
    }
  }
}

让我们发布一些文件：

POST my_index/_doc/1
{    
    "category": "clothing (m)",
    "description": "Women's Unstoppable Graphic T-Shirt - Women’s Short Sleeve Shirt",
    "name": "Women's Unstoppable Graphic T-Shirt",
    "price": "$34.99"
}


POST my_index/_doc/2
{    
    "category": "clothing (f)",
    "description": "Women's Unstoppable Graphic T-Shirt - Women’s Short Sleeve Shirt",
    "name": "Women's Unstoppable Graphic T-Shirt",
    "price": "$34.99"
}

现在我们的查询应该是这样的：

GET my_index/_search
{
  "query": {
    "bool": {
      "must": {
        "match": {
          "description": "women's black shirt"
        }
      },
      "filter": {
        "bool": {
          "must_not": {
            "term": {
              "category.keyword": "clothing (m)"
            }
          }
        }
      }
    }
  },
  "from": 0,
  "size": 50
}

结果：

{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 0.43301374,
    "hits" : [
      {
        "_index" : "my_index",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 0.43301374,
        "_source" : {
          "category" : "clothing (f)",
          "description" : "Women's Unstoppable Graphic T-Shirt - Women’s Short Sleeve Shirt",
          "name" : "Women's Unstoppable Graphic T-Shirt",
          "price" : "$34.99"
        }
      }
    ]
  }
}

不使用keyword结果

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 0.43301374,
    "hits" : [
      {
        "_index" : "my_index",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : 0.43301374,
        "_source" : {
          "category" : "clothing (f)",
          "description" : "Women's Unstoppable Graphic T-Shirt - Women’s Short Sleeve Shirt",
          "name" : "Women's Unstoppable Graphic T-Shirt",
          "price" : "$34.99"
        }
      },
      {
        "_index" : "my_index",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : 0.43301374,
        "_source" : {
          "category" : "clothing (m)",
          "description" : "Women's Unstoppable Graphic T-Shirt - Women’s Short Sleeve Shirt",
          "name" : "Women's Unstoppable Graphic T-Shirt",
          "price" : "$34.99"
        }
      }
    ]
  }
}

正如您从上次结果中看到的，我们还得到了服装 (m) 。 顺便说一句，不要对text数据类型使用term 。 使用match 。

希望这可以帮助。