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elasticsearchdslelasticsearch-dsl

How to get exact match phrase more than one


Below is the query to get the exact match

GET courses/_search
{
  "query": {
    "term" : {
         "name.keyword": "Anthropology 230"
      }
  }
}

I need to find the Anthropology 230 and Anthropology 250 also

How to get the exact match


Solution

  • The mistake that you are doing is that you are using the term query on keyword field and both of them are not analyzed, which means they try to find the exact same search string in inverted index.

    What you should be doing is: define a text field which you anyway will have if you have not defined your mapping. I am also assuming the same as in your query you mentioned .keyword which gets created automatically if you don't define mapping.

    Now you can just use below match query which is analyzed and uses standard analyzer which splits the token on whitespace, so Anthropology 250 and 230 will be generated for your 2 sample docs.

    Simple and efficient query which brings both the docs

    {
        "query": {
            "match" : {
                "name" : "Anthropology 230"
            }
        }
    }
    

    And search result

     "hits": [
          {
            "_index": "matchterm",
            "_type": "_doc",
            "_id": "1",
            "_score": 0.8754687,
            "_source": {
              "name": "Anthropology 230"
            }
          },
          {
            "_index": "matchterm",
            "_type": "_doc",
            "_id": "2",
            "_score": 0.18232156,
            "_source": {
              "name": "Anthropology 250"
            }
          }
        ]
    

    The reason why above query matched both docs is that it created two tokens anthropology and 230 and matches anthropology in both of the documents.

    You should definitely read about the analysis process and can also try analyze API to see the tokens generated for any text.

    Analyze API output for your text

    POST http://{{hostname}}:{{port}}/{{index-name}}/_analyze

    {
      "analyzer": "standard",
      "text": "Anthropology 250"
    }
    
    
    {
        "tokens": [
            {
                "token": "anthropology",
                "start_offset": 0,
                "end_offset": 12,
                "type": "<ALPHANUM>",
                "position": 0
            },
            {
                "token": "250",
                "start_offset": 13,
                "end_offset": 16,
                "type": "<NUM>",
                "position": 1
            }
        ]
    }