title: try to get data from Firebase that under two unique keys generated by UID and push() method and using a query
body: <p>I used a query that take a specific date from the user to get data from the database but it keep saying that the data is noted existing even if I used two-loop one over the Uid and one over push key.
  here is the code I write.    </p>
  
  <pre><code>final DatePickerDialog datePickerDialog = new DatePickerDialog(AdminAppointmentManage.this, new DatePickerDialog.OnDateSetListener() {
      @Override
      public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
          month += 1;
          selectedDate = dayOfMonth + "/" + month + "/" + year;
          dateText.setText(selectedDate);
          Query query = FirebaseDatabase.getInstance().getReference().child("Appointment").orderByChild("dateOfAppointment").equalTo(selectedDate);
          query.addValueEventListener(new ValueEventListener() {
              @Override
              public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                  appointmentList.clear();
                  List&lt;String&gt; appointmentKey = new ArrayList&lt;&gt;();
                  if (dataSnapshot.exists()) {
                      for (DataSnapshot snapshot : dataSnapshot.getChildren()) {
                          for (DataSnapshot appointmentSnapshot : snapshot.getChildren()){
                              appointmentKey.add(appointmentSnapshot.getKey());
                              Appointments appointments = appointmentSnapshot.getValue(Appointments.class);
                              appointmentList.add(appointments);
                      }}
                      adapter.notifyDataSetChanged();
                  } else {
                      Toast.makeText(AdminAppointmentManage.this, "No Appointment for that day !!", Toast.LENGTH_SHORT).show();
                  }
              }
  
              @Override
              public void onCancelled(@NonNull DatabaseError databaseError) {
  
              }
          });
      }
  }, year, month, day);
  </code></pre>
  
  <p>the database tree : </p>
  
  <p><img src="https://i.stack.imgur.com/28Mai.png" alt="enter image description here"></p>