Display Firebase Keys that has a specific children values

Question

I want to be able to check the keys from my database whose child has a value that matches a specific value. For example, My keys are:
- A
- B
- C;
Each key has a child called Verified that either has a value of true or false. Currently, I can display all the keys using the code below. What I don't understand is how can I display the same keys but only the ones whose child verified == "True"

if let snapDict = snapshot.value as? [String:AnyObject]
     {
           for each in snapDict
           {
               let  names = each.key
               let initialisation = ListOfNames(names: names)
               self.names.insert(initialisation, at: 0)
           }
      }

Answer 1

You have to index your data on the key

https://firebase.google.com/docs/database/security/indexing-data

and then you must query your data

https://firebase.google.com/docs/reference/js/firebase.database.Query