Advanced MySQL query

Hello,

I’m trying to compose a quite complex MySQL query and don’t seem to get my head around it (I’m not a MySQL pro).
The query should return the published post(s) that have one or more approved comment which match a search term (this part works fine!) and aren’t listed in one or more particular categories (that’s where I’m stuck).

Here’s my code:

SELECT DISTINCT c.comment_ID AS unionCommentID, p.ID AS unionID, p.post_date AS unionDate, p.post_title AS unionTitle, c.comment_content AS unionDescription, c.comment_author AS unionAuthor, p.post_name AS unionSlug, p.post_name AS unionPermalink, 'comment' AS unionType,
MATCH (
c.comment_content
)
AGAINST (
'search_term'
) AS relevancy
FROM wp_comments AS c, wp_posts AS p, wp_terms AS t, wp_term_taxonomy AS tt, wp_term_relationships AS tr
WHERE p.ID = c.comment_post_ID
AND p.ID = tr.object_id
AND tr.term_taxonomy_id = tt.term_taxonomy_id
AND t.term_id = tt.term_id
AND
t.term_id NOT
IN (
'1', '2', '3', '25'
)
AND p.post_status = 'publish'
AND c.comment_approved = '1'
AND MATCH (
c.comment_content
)
AGAINST (
'search_term'
)

ANY help or hint would be highly appreciated.
Thanks a lot,
—trice