You should put the entire case statment for "Publisher" in the group by.

Pratap

pratap_fin (AT) rediffmail (DOT) com (Pratap) wrote in message news:<830861d2.0408312306.661a50c3 (AT) posting (DOT) google.com>...
Thanks Pratap, but i forgot to mention that i tried that already, and
it didn't work.

Anyone else?

I suggest you add an inline view -
(
SELECT p.pub_nm, b.ean_no FROM publisher p, book b
WHERE p.pub_id=b.pub_id ) publisher

Then outer join publisher and merchandise
publisher.ean_no (+) = m.ean_no

And instead of the case statement in the select, simply put -

nvl(publisher.pub_nm, 'n/a') "Publisher",

Then group by nvl(publisher.pub_nm, 'n/a')

Hope this helps. Next time post the table creation scripts also, so
that the error can be reproduced at my end.

Pratap

PS -
CASE
WHEN m.merch_type_cd='BOOK'
THEN( SELECT p.pub_nm FROM publisher p, book b
WHERE p.pub_id=b.pub_id AND b.ean_no=m.ean_no AND ROWNUM =1
GROUP BY p.pub_nm)
ELSE 'n/a'

You do not need a GROUP BY p.pub_nm here.