Объясните, пожалуйста, что должен найти данный запрос

SELECT p1.pub_id
FROM titles t1, publishers p1
WHERE t1.pub_id=p1.pub_id
GROUP BY p1.pub_id
HAVING COUNT(DISTINCT title)=
(SELECT COUNT(*)
FROM titles t2
WHERE t2.pub_id=p1.pub_id
AND EXISTS
(SELECT *
FROM titleauthor ta3, authors a3
WHERE ta3.au_id=a3.au_id
AND ta3.title_id=t2.title_id
AND a3.state IN
(SELECT state
FROM publishers p4
WHERE "business"=SOME
(SELECT type
FROM titles t5
WHERE p4.pub_id=
t5.pub_id))))