select distinct postgres 9.2

Hi guys,

I've got the following query:

WITH
> accounts AS (
> SELECT
> c.id AS company_id,
> c.name_first AS c_first_name,
> c.name_last AS c_last_name,
> c.company AS c_name,
> FROM public.clients c
> WHERE id = 33412393
> ORDER BY 1 LIMIT 100
> )
> SELECT
> r.parts[4]::INT AS account_id,
> r.parts[6]::INT AS n_id,
> r.parts[9] AS variation,
> size,
> FROM (
> SELECT
> string_to_array(full_path, '/') AS parts,
> size
> FROM public.segments s
> WHERE public.f_get_account_from_full_path(s.full_path) IN (SELECT
> company_id FROM accounts)
> ) r

... and I want to get only the greatest note_id order by size,

How can I put this query into the above one?

> SELECT DISTINCT ON
> (n_id) n_id,
> MAX(size)
> FROM
> test1
> GROUP BY
> note_id, size, st_ino, account_id
> ORDER BY
> note_id, size desc

DISTINCT ON (r.parts[6]::INT) AS n_id - it doesn't work...

Thanks
Patrick