title: How to return results where a field starts with a specific letter or letters in Elasticsearch?
body: <p>I have some data like</p>
  
  <pre><code>"last_name": "AA-WEST"
  "last_name": "VANDER AA"
  "last_name": "ARENDES-AA"
  </code></pre>
  
  <p>And I'm trying to only get names that start with <code>a</code>, i.e. <code>AA-WEST</code> and <code>ARENDES-AA</code></p>
  
  <p>I've tried</p>
  
  <pre><code>"match": {
      "last_name": {
          "query": "a",
          "operator": "and"
      }
  }
  </code></pre>
  
  <p>and</p>
  
  <pre><code>"prefix": {
      "last_name": { "value" : "a" }
  }
  </code></pre>
  
  <p>and</p>
  
  <pre><code>"match_phrase_prefix": {
      "last_name.keyword": {
          "query": "a"
      }
  }
  </code></pre>
  
  <p>All of these will return all names, not only that really start with <code>a</code></p>
  
  <p>Any ideas?</p>