title: Firebase: Query to exclude data based on a condition
body: <p>I'm able to get the data for a particular value in the child using <code>orderByChild</code> and <code>equalTo</code> (cool that it works for nested child as well) </p>
  
  <pre><code>private void getData() {
          try {
              final DatabaseReference database = FirebaseDatabase.getInstance().getReference();
  
              database.child(Constants.TABLE_TASKS).orderByChild("user/id")
                      .equalTo("somevalue")
                      .addValueEventListener(new ValueEventListener() {
                          @Override
                          public void onDataChange(DataSnapshot dataSnapshot) {
                              Timber.d(dataSnapshot.toString());
                          }
  
                          @Override
                          public void onCancelled(DatabaseError databaseError) {
                          }
                      });
          } catch (Exception ex) {
              ex.printStackTrace();
          }
      }
  </code></pre>
  
  <p>Is there an easy way to get the data where a particular value is not found, basically something like a <code>notEqualTo("somevalue")</code> ? </p>