Count associations in sqlite database query? - sql

Question

I have a sqlite database with three tables: Notes, Lists, and Notes-in-Lists.
Both Notes and Lists have an autogenerated id column and some extra data columns like title. Notes-in-Lists is an association table with an autokey, and two foreign keys that point to a Note id and a List id.
I have a query that returns all notes in a given list:
Select _id, title From Notes
Join Notes_in_Lists On Notes._id=Notes_in_Lists.note_id
Where Notes_in_Lists.list_id=2
This would return all note titles and ids from List 2 for example.
However, notes can be in multiple lists and I need to be able to tell if a note is associated with multiple lists. This is indicated by the same Notes_in_Lists.note_id being listed multiple times in the Notes_in_Lists table.
Easy enough to do by itself:
Select Count(note_id) From Notes_in_Lists Where note_id=2
But I need to combine the two queries above into one query and I have not idea where to begin.
Edit
Sample data
Notes:
_id title
1 "Note 1"
2 "Note 2"
3 "Note 3"
4 "Note 4"
Note_in_Lists
_id note_id list_id
1 1 2
2 1 3
3 2 2
4 3 1
5 4 2
6 4 4
7 4 5
Sample output (query for contents of list 2):
_id title numberOfLists
1 "Note 1" 2
2 "Note 2" 1
4 "Note 4" 3

Answer 1

Select Notes._id, Notes.title, Count(Nil2.list_id)
From Notes
Inner Join Notes_in_Lists NiL1 On Notes._id=NiL1.note_id
Inner Join Notes_in_Lists NiL2 On Notes._id=NiL2.note_id
Where NiL1.list_id=2
Group By Notes._id, Notes.title;
It can seem wasteful to do two joins, but that's what you need to basically run two queries.

Answer 2

SELECT n._ID, Title, Count(*) numberOfLists
FROM Notes n, Notes_In_Lists l
where n._id = l.note_id
AND NOT EXISTS (Select 1
from notes_in_lists l2 where
l2.note_Id = n._id
AND l._Id = 2)
group by n._ID, n.Title