mbrainz=# \d artistwords
Table "public.artistwords"
  Column  |  Type   | Modifiers 
----------+---------+-----------
 wordid   | integer | not null
 artistid | integer | not null

mbrainz=# \d artist
Table "public.artist"
     Column      |          Type          |                      Modifiers                      
-----------------+------------------------+-----------------------------------------------------
 id              | integer                | not null default nextval('artist_id_seq'::regclass)
 name            | character varying(255) | not null
 gid             | character(36)          | not null
 modpending      | integer                | default 0
 sortname        | character varying(255) | not null
 page            | integer                | not null
 resolution      | character varying(64)  | 
 begindate       | character(10)          | 
 enddate         | character(10)          | 
 type            | smallint               | 
 quality         | smallint               | default -1
 modpending_qual | integer                | default 0


mbrainz=# \d wordlist
Table "public.wordlist"
     Column     |          Type          |                       Modifiers                       
----------------+------------------------+-------------------------------------------------------
 id             | integer                | not null default nextval('wordlist_id_seq'::regclass)
 word           | character varying(255) | not null
 artistusecount | smallint               | not null default 0
 albumusecount  | smallint               | not null default 0
 trackusecount  | smallint               | not null default 0
 labelusecount  | smallint               | not null default 0

Now I wanted to do a query on any number of words, match the word ids with the word, and then following match
the artist that has references to all those words. My attempt as as follows:

SELECT a.name AS artist_name
  FROM artist a
  WHERE NOT EXISTS
(
     SELECT * 
       FROM artistwords aw
       WHERE a.id = aw.artistid
         AND
           aw.wordid NOT IN 
            (
                SELECT id from wordlist where (word = 'bob' OR word = 'dylan')
            )
)

Unfortunately this only yields:
artist_name
Bob!
Bob
Bob
Bob
BOB
Dylan
bob.
Bob
bob
Bob

Which is fine, where it not that Bob Dylan is actually lacking; which I do not understand.