# ElasticSearch Keyword usage with a prefix search

**URL:** <https://discuss.elastic.co/t/elasticsearch-keyword-usage-with-a-prefix-search/248695>\
**Category:** Elasticsearch\
**Created:** [September 15, 2020, 2:20pm UTC](https://discuss.elastic.co/t/elasticsearch-keyword-usage-with-a-prefix-search/248695 "2020-09-15T14:20:14Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Sunilbvr](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/sunilbvr/32/46322_2.png) [@Sunilbvr](https://discuss.elastic.co/u/Sunilbvr)\
**Post date:** [September 15, 2020, 2:20pm UTC](https://discuss.elastic.co/t/elasticsearch-keyword-usage-with-a-prefix-search/248695/1 "2020-09-15T14:20:15Z")

</div>

I have a requirement to be able to search a sentence as complete or with prefix. The UI library (reactive search) I am using is generating the query in this way:

```auto
"simple_query_string": {
  "query": "\"Louis George Maurice Adolphe\"",
  "fields": [
    "field1",
    "field2",    
    "field3"
  ],
  "default_operator": "or"
}

```

I am expecting it to returns results for eg.  
`Louis George Maurice Adolphe (Roche)`  
but NOT just records containing partial terms like `Louis` or `George`

Currently, I have code like this but it only brings the record if I search with complete word `Louis George Maurice Adolphe (Roche)` but not a prefix `Louis George Maurice Adolphe`.

```auto
{
  "settings": {
    "analysis": {
      "char_filter": {
        "space_remover": {
          "type": "mapping",
          "mappings": [
            "\\u0020=>"
          ]
        }
      },
      "normalizer": {
        "lower_case_normalizer": {
          "type": "custom",
          "char_filter": [
            "space_remover"
          ],
          "filter": [
            "lowercase"
          ]
        }
      }
    }
  },
  "mappings": {
    "_doc": {
      "properties": {
        "field3": {
          "type": "keyword",
          "normalizer": "lower_case_normalizer"
        }
      }
    }
  }
}

```

Any guidance on the above is appreciated. Thanks.

Note: The issue here is the user queries it through a search box and the library generates the `simple_query_string` . The user's search term can match any of the fields field1, field2, field3 or field4. How can I change the query by still maintaining this functionality? And all the fields can be linked to different analyzers

---

<div class="post-metadata">

**Author:** ![Emanuil](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/emanuil/32/36783_2.png) [@Emanuil](https://discuss.elastic.co/u/Emanuil)\
**Post date:** [September 16, 2020, 1:43am UTC](https://discuss.elastic.co/t/elasticsearch-keyword-usage-with-a-prefix-search/248695/2 "2020-09-16T01:43:25Z")

</div>

I'd have said use a Prefix query, but it sounds like you can't change the query type the UI library is producing. Maybe it has an option to issue a different query?

Otherwise you might want to look at the [wildcard field type](https://www.elastic.co/guide/en/elasticsearch/reference/7.9/keyword.html#wildcard-field-type). Its full-length matches (keyword-style) are a bit slower than if you used a keyword field, but they work - plus it enables the efficient use of wildcard queries, including wildcards in the simple query string query. Only thing is, [it just got introduced in 7.9](https://www.elastic.co/guide/en/elasticsearch/reference/current/release-highlights.html#_wildcard_field_optimised_for_wildcard_queries) so you might need to upgrade.

This is what I ran:

```auto
PUT index1
{
  "settings": {
    "analysis": {
      "char_filter": {
        "space_remover": {
          "type": "mapping",
          "mappings": [
            "\\u0020=>"
          ]
        }
      },
      "normalizer": {
        "lower_case_normalizer": {
          "type": "custom",
          "char_filter": [
            "space_remover"
          ],
          "filter": [
            "lowercase"
          ]
        }
      }
    }
  },
  "mappings": {
      "properties": {
        "field3": {
          "type": "keyword",
          "normalizer": "lower_case_normalizer"
        },
        "field3_wildcard": {
          "type": "wildcard"
        }
      }
  }
}

```

So far, so good, I just introduce a wildcard field alongside your keyword field so we can play more easily.

```auto
POST index1/_doc
{
  "field3": "Louis George Maurice Adolphe (Roche)",
  "field3_wildcard": "Louis George Maurice Adolphe (Roche)"
}

```

`GET index1/_search` if you want to check it's been indexed.

```auto
POST index1/_search
{
  "query": {
    "simple_query_string": {
      "query": "\"Louis George Maurice Adolphe*\"",
      "fields": [  
        "field3_wildcard"
      ],
      "default_operator": "or"
    }
  }
}

```

That finds the document. Only thing I've changed is to add the \* wildcard at the end, to indicate `Louis George Maurice Adolphe` is a prefix. This doesn't work with a keyword field because that needs an exact full match. `"query": "\"Louis George Maurice Adolphe (Roche)\"",` (exact match) also works with `wildcard`.

I think this fulfils

> I have a requirement to be able to search a sentence as complete or with prefix

Though it requires `*`s added to your queries.

---

<div class="post-metadata">

**Author:** ![Sunilbvr](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/sunilbvr/32/46322_2.png) [@Sunilbvr](https://discuss.elastic.co/u/Sunilbvr)\
**Post date:** [September 16, 2020, 10:23am UTC](https://discuss.elastic.co/t/elasticsearch-keyword-usage-with-a-prefix-search/248695/3 "2020-09-16T10:23:30Z")

</div>

> [@Emanuil](#):
>
> it just got introduced in 7.9

Hi Emanuil,

This sounds like a reasonable solution. I will try it with my data.

Thank you very much

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [October 14, 2020, 10:23am UTC](https://discuss.elastic.co/t/elasticsearch-keyword-usage-with-a-prefix-search/248695/4 "2020-10-14T10:23:37Z")

</div>

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