# Retrieve Search Results Based on the First Letter in a Specific Field

**URL:** <https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852>\
**Category:** Elasticsearch\
**Created:** [June 14, 2019, 12:11pm UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852 "2019-06-14T12:11:06Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 14, 2019, 12:11pm UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/1 "2019-06-14T12:11:06Z")

</div>

Hey,

Is it possible to search based on the first letter in a specified field of documents?

for example, when the query is letter 'A", all documents that have titles that start with 'A' are returned.

thanks.

---

<div class="post-metadata">

**Author:** ![wangqinghuan](https://avatars.discourse-cdn.com/v4/letter/w/d26b3c/32.png) [@wangqinghuan](https://discuss.elastic.co/u/wangqinghuan)\
**Post date:** [June 15, 2019, 12:38pm UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/2 "2019-06-15T12:38:43Z")

</div>

Using wildcard query . Here is a example:  
GET /\_search

> ```
> {
> "query": {
> "wildcard": {
> "title": {
> "value": "A*"
> }
> }
> }
> }
> 
> ```

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 16, 2019, 4:39am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/3 "2019-06-16T04:39:19Z")

</div>

Note that this can be slow.  
Another query could be: [Prefix query | Elasticsearch Guide [8.11] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-prefix-query.html)

> [@maryam\_abdullah](#):
>
> when the query is letter 'A", all documents that have titles that start with 'A' are returned.

If you can wait for more letters to be entered, like AB or ABC before launching the search, I'd use a edge ngram based analyzer strategy. See [Edge NGram Tokenizer | Elasticsearch Guide [7.1] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/7.1/analysis-edgengram-tokenizer.html)

And even better/faster I'd use a completion suggester. [Completion Suggester | Elasticsearch Guide [7.1] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/7.1/search-suggesters-completion.html)

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 17, 2019, 5:27am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/4 "2019-06-17T05:27:43Z")

</div>

@dadoonet No , the scenario isn't based on waiting for more letters.  
I've tried both the prefix query and wildcard,  
and noticed that if the field contains multiple words then all titles that have words that start with an "A" for example will be retrieved, not based on the first word in that field.

Any thoughts about how this can be solved?

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 17, 2019, 6:31am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/5 "2019-06-17T06:31:38Z")

</div>

Could you provide a full recreation script as described in [About the Elasticsearch category](https://discuss.elastic.co/t/about-the-elasticsearch-category/21). It will help to better understand what you are doing. Please, try to keep the example as simple as possible.

A full reproduction script will help readers to understand, reproduce and if needed fix your problem. It will also most likely help to get a faster answer.

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 17, 2019, 6:35am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/6 "2019-06-17T06:35:49Z")

</div>

Okay.

Here's the code for creating the index with its settings and mappings:

```
var response = client.CreateIndex(index, c => c
                 .Mappings(ms => ms
                     .Map<Document>(m => m
                         .Properties(ps => ps
                             .Text(n => n
                                 .Name(e => e.Id))
                             .Keyword(s => s
                                 .Name(n => n.Client))
                             .Text(s => s
                                 .Name(n => n.Title)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.Summary)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.Content)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.Tags)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.Url))
                             .Text(s => s
                                 .Name(n => n.Image))
                             .Date(s => s
                                 .Name(n => n.Date))
                             .Number(s => s
                                 .Name(n => n.Importance))
                             .Text(s => s
                                 .Name(n => n.Terms)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.MainTerms)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.Meta)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.Type)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.Info))
                             .Text(s => s
                                 .Name(n => n.Relations)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             .Text(s => s
                                 .Name(n => n.RelationsSummary)
                                 .Analyzer("english_analyzer")
                                 .Fields(f => f.Text(t => t.Analyzer("english_standard").Name("exact"))))
                             )
                         ))
                 .Settings(ss => ss
                    .NumberOfShards(5)
                     .Analysis(an => an
                         .TokenFilters(tf => tf
                             .Stop("english_stop", ts => ts
                                 .StopWords("_english_"))
                             .KeywordMarker("english_keywords", km => km.KeywordsPath(keywordsFile))
                             .Stemmer("english_stemmer", st => st.Language("english"))
                             .Stemmer("english_possessive_stemmer", st => st.Language("possessive_english"))
                         )
                         .Analyzers(ns => ns
                             .Custom("english_analyzer", cm => cm
                                 .Tokenizer("standard")
                                 .Filters("english_possessive_stemmer", "lowercase", "english_stop", "english_keywords", "english_stemmer")
                             )
                             .Custom("english_standard", cm => cm
                                 .Tokenizer("standard")
                                 .Filters("english_possessive_stemmer", "lowercase")
                             ))
                     )
                 )
             );

```

The following is the search query:

```
var response = elasticClient.Search<Document>(s => s
                .From(offset)
                .Size(size)
                .Index(name)
                .Sort(so => sortByDate
                    ? so.Descending(a => a.Date).Field(f => f.Field("_score").Order(SortOrder.Descending))
                    : so.Field(f => f.Field("_score").Order(SortOrder.Descending)))
                    
                .Query(q => q
                        //m => m.Prefix(p => p.Field(f => f.Title).Boost(20).Value("a"))
                       // m => m.Wildcard(w => w.Field(f => f.Title).Value("a*")),
                      .SpanFirst(sf => sf.Match(mm => mm.SpanTerm(st => st.Field(f => f.Title).Value("a"))).End(1).Boost(100))
                                    )
            );

```

I tried to use span first as well, but it hasn't returned any result.

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 17, 2019, 6:58am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/7 "2019-06-17T06:58:10Z")

</div>

Could you provide something I can test in Kibana dev console?

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 17, 2019, 7:06am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/8 "2019-06-17T07:06:05Z")

</div>

I will try to rewrite it in curl.

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 17, 2019, 7:26am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/9 "2019-06-17T07:26:52Z")

</div>

```
PUT en
{
  "mappings": {
    "properties": {
      "Id": {
        "type": "text"
      },
      "Title": {
        "type": "text",
        "analyzer": "english_analyzer",
        "fields": {
          "exact": {
            "type": "text",
            "analyzer": "english_standard"
          }
        }
      }
    }
  },
  "settings": {
    "number_of_shards": 5,
    "analysis": {
      "filter": {
        "english_stop": {
          "type": "stop",
          "stopwords": "_english_"
        },
        "english_stemmer": {
          "type": "stemmer",
          "language": "english"
        },
        "english_possessive_stemmer": {
          "type": "stemmer",
          "language": "possessive_english"
        }
      },
      "analyzer": {
        "english_analyzer": {
          "tokenizer": "standard",
          "filter": [
            "english_possessive_stemmer",
            "lowercase",
            "english_stop",
            "english_stemmer"
          ]
        },
        "english_standard": {
          "tokenizer": "standard",
          "filter": [
            "english_possessive_stemmer",
            "lowercase"
          ]
        }
      }
    }
  }
}

PUT en/_doc/1
  {
        "id": "de22b1fd-8383-11e9-80bf-0cc47a868a49",
        "title": "Articles"
  }

 PUT en/_doc/2
      {
            "id": "33efc673-86ab-11e9-80bf-0cc47a868a49",
            "title": "WhatsApp: Adverts coming to messaging app next year, Facebook reveals"
      }

 GET /_search
    {
        "query": {
            "span_first" : {
                "match" : {
                    "span_term" : { "Title" : "a" }
                },
                "end" : 1
            }
        }
    }
```

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 17, 2019, 8:59am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/10 "2019-06-17T08:59:49Z")

</div>

Could you add a sample document to your script?

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 17, 2019, 9:20am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/11 "2019-06-17T09:20:53Z")

</div>

```
[
  {
    "id": "33efc673-86ab-11e9-80bf-0cc47a868a49",
    "title": "WhatsApp: Adverts coming to messaging app next year, Facebook reveals"
  },
  {
    "id": "f5b77d15-86a9-11e9-80bf-0cc47a868a49",
    "title": "New York City terror attack: what we know so far"
  },
  {
    "id": "de22b1fd-8383-11e9-80bf-0cc47a868a49",
    "title": "Articles"
  }
]
```

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 17, 2019, 11:38am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/12 "2019-06-17T11:38:55Z")

</div>

Is that one document? Could you please add it to your script so anyone can just copy and paste and run it from Kibana?

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 17, 2019, 11:50am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/13 "2019-06-17T11:50:18Z")

</div>

No, these are three documents.

Yes, I will add them to the above code.

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 17, 2019, 12:50pm UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/14 "2019-06-17T12:50:15Z")

</div>

Please read again the instructions I gave earlier. We should be able to just copy and paste the script in Kibana and run it. Here this won't work.

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 18, 2019, 5:20am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/15 "2019-06-18T05:20:32Z")

</div>

I updated it.

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 20, 2019, 1:18pm UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/16 "2019-06-20T13:18:34Z")

</div>

I updated it a bit. Not sure if this is what you are looking for though.

```auto
DELETE en
PUT en
{
  "mappings": {
    "properties": {
      "title": {
        "type": "text",
        "analyzer": "simple"
      }
    }
  }
}

PUT en/_doc/1
{
  "title": "Articles"
}
PUT en/_doc/2
{
  "title": "Foo Articles"
}

GET /_search
{
  "query": {
    "prefix": {
      "title": "a"
    }
  }
}

```

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 20, 2019, 3:06pm UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/17 "2019-06-20T15:06:19Z")

</div>

I'm getting an error while executing the index creation script.  
`Failed to parse mapping [properties]: Root mapping definition has unsupported parameters: [title : {analyzer=simple, type=text}]`  
So, using a simple analyzer made the prefix search return only documents that start with an 'a' letter, in that case, it returned the doc with id 1 only, am I right?  
The thing is I need to have 2 different analyzers as I stated earlier.

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 20, 2019, 5:33pm UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/18 "2019-06-20T17:33:02Z")

</div>

> The thing is I need to have 2 different analyzers as I stated earlier.

Sure. You can have multiple subfields generated at index time with a different analyzer to support another use case.

See [fields | Elasticsearch Guide [8.11] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/current/multi-fields.html)

---

<div class="post-metadata">

**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [June 20, 2019, 5:33pm UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/19 "2019-06-20T17:33:34Z")

</div>

> [@maryam\_abdullah](#):
>
> I'm getting an error while executing the index creation script.

That's probably because you are not using 7.x.

---

<div class="post-metadata">

**Author:** ![maryam\_abdullah](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@maryam\_abdullah](https://discuss.elastic.co/u/maryam_abdullah)\
**Post date:** [June 21, 2019, 6:44am UTC](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852/20 "2019-06-21T06:44:58Z")

</div>

Well, the prefix query returned both documents.  
I need the document with id = 1 to be returned only and not both documents.

What I meant is that the position of words matter. And the matching needs to happen based on the first word of the title field.

[Next page](https://discuss.elastic.co/t/retrieve-search-results-based-on-the-first-letter-in-a-specific-field/185852.md?page=2)