title: I want call data form subcollection with specific data
body: <p>I want call data from subcollection with specific data that I highlight
  <img src="https://i.stack.imgur.com/vPYd6.png" alt="" /></p>
  <pre><code>export class FirebaseService {
  
      onsiteRef: AngularFirestoreCollectionGroup&lt;Onsiteinterface&gt;;
  
      constructor(private db: AngularFirestore, public ngFireAuth: 
      AngularFireAuth)  { 
          this.onsiteRef = db.collectionGroup('Request', ref =&gt; 
          ref.where('Onsite','==','Onsite'));
      }
  </code></pre>