Android :: SQL Efficiently Check - An Association Exists

I have a database of notes and lists, with three association tables.
Basically, lists are parents of notes and other lists, and notes can be parents of other notes in a outline like hierarchy.

I am using this query to return all notes within a list as well as the number of subnotes each note has.

CODE:...................

This query works just fine, but it's overkill. I don't need to return count(n2.note_id) as Num_Subnotes because I'm only using that value to check if the note has ANY SUBNOTES AT ALL. Essentially it's a boolean value where 0 is false and > 0 is true.

It seems to me that counting all those records is a waste of time when I could just return 1 after finding the first matching value.

Is there a more efficient way to check if count(n2.note_id)>0 in the above query?