title: Firebase: How to retrieve two values for the same key query?
body: <p>What I am trying to do is to query Firebase for two values with the same key.
  My database is like this:</p>
  
  <pre><code>"Document" : [ {
      "fileType" : "PDF",
      "language" : "en",
      "linkUrl" : "https://myfile.pdf",
      "name" : "Installation Guide"
    }, {
      "fileType" : "DOCUMENT",
      "language" : "fr",
      "linkUrl" : "https://myfile.txt",
      "name" : "text.txt"
    }
  </code></pre>
  
  <p>I have written a query in my Android project to retrieve all documents with the same language and it works.</p>
  
  <pre><code>val selectedLanguage = LocalStorageHelper.getInstance(this)?.getSelectedLanguage()
  val docRef = rootRef.child("Document").orderByChild("language").equalTo("en")
  </code></pre>
  
  <p>But now what I would like to do is, look for "en" and "fr".</p>
  
  <p>Is it possible to do like the above, I have searched online but didn't find anything positive on this.</p>