title: Android - How to query in firebase
body: <p>Basically I have to listen a object. Please see the attached images.</p>
  
  <p><a href="https://i.stack.imgur.com/RYgEt.png" rel="nofollow noreferrer">Memo List</a></p>
  
  <p><a href="https://i.stack.imgur.com/FxLlc.png" rel="nofollow noreferrer">Memo Object</a></p>
  
  <p>So I need to get all <code>memos</code> which equal to <code>hash_tag = "love"</code>. How to overcome this problem?</p>
  
  <pre><code>Query query = memo.child(Memo.HASH_TAG).startAt("love");
  query.addChildEventListener(mMemoChildEventListener);
  </code></pre>