Outer Join on 3 tables

[Gary Townsend]

I am using Postgres 7.4.6 i have 3 tables i want to join 3 tables and
return a list of route_id to which a specified user_id does NOT belong.
Table "public.vts_use rs"
Column | Type | Modifiers
------------+------------------------+--------------------------------------
--------------------------
user_id | integer | not null default
nextval('public .vts_users_user _id_seq'::text)
username | character varying(255) | not null
password | character varying(50) |
role_id | integer |
first_name | character varying(50) |
last_name | character varying(50) |
timezone | character varying(3) | default 'MST'::characte r varying
Indexes:
"vts_users_pkey " primary key, btree (user_id)
"vts_users_user name_key" unique, btree (username)
Foreign-key constraints:
"$1" FOREIGN KEY (role_id) REFERENCES vts_roles(role_ id)

vtsdev=# \d vts_routes
Table "public.vts_rou tes"
Column | Type |
Modifiers
--------------------+------------------------+------------------------------
------------------------------------
route_id | integer | not null default
nextval('public .vts_routes_rou te_id_seq'::tex t)
route_name | character varying(50) |
route_descripti on | character varying(255) |
always_web_visi ble | boolean | not null default false
school_id | integer |
Indexes:
"vts_routes_pke y" primary key, btree (route_id)
Check constraints:
"route_name _nn" CHECK (route_name IS NOT NULL)

vtsdev=# \d vts_parent_rout e_link
Table "public.vts_par ent_route_link"
Column | Type | Modifiers
-----------+---------+------------------------------------------------------
------------------------
prlink_id | integer | not null default
nextval('public .vts_parent_rou te_link_prlink_ id_seq'::text)
user_id | integer |
route_id | integer |
Indexes:
"vts_parent_rou te_link_pkey" primary key, btree (prlink_id)
"vts_parent_rou te_link_user_id _key" unique, btree (user_id, route_id)
Check constraints:
"user_id_nn " CHECK (user_id IS NOT NULL)
"route_id_n n" CHECK (route_id IS NOT NULL)
Foreign-key constraints:
"$1" FOREIGN KEY (user_id) REFERENCES vts_users(user_ id)
"$2" FOREIGN KEY (route_id) REFERENCES vts_routes(rout e_id)