title: How can I query multiple different sub collection at ones?
body: <p>Recently I am building a recipe app. I am using firebase as my database. Now I want to let the users to find any recipe which I have stored in my recipe Collection.<a href="https://i.stack.imgur.com/GezUz.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GezUz.png" alt="enter image description here" /></a></p>
  <p>Each Food_Recipe has different subcollections. I'll explain my issue using an example.
  <a href="https://i.stack.imgur.com/kAbsp.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kAbsp.png" alt="enter image description here" /></a></p>
  <p>Now, I want to find the document which Recipe_name == Biriyani.
  I could archive my goal easily using this way,</p>
  <pre><code>  Query query = FirebaseFirestore.getInstance().collection(&quot;Recipes&quot;).document(&quot;Food_Recipe&quot;)
              .collection(&quot;Rice_Recipe&quot;).orderBy(&quot;Recipe_name&quot;)
              .startAt(InputSearchText).endAt(InputSearchText +&quot;\uf8ff&quot;);
  </code></pre>
  <p>But I need to get the same result across the Recipe Collection.
  For example, Just imaging, if Powder_Recipe also have a Recipe_name Biriyani, there should be 2 result from different subcollections.</p>