CREATE TABLE book (book_id NUMBER, title CLOB, issues NUMBER, writer CLOB)
CREATE TABLE publication (publication_id NUMBER, book_id NUMBER, publisher CLOB, publication_date CLOB, price NUMBER)

Show publishers that have more than one publication.
SELECT publisher FROM publication GROUP BY publisher HAVING COUNT(*) > 1
SELECT "publisher" FROM "publication" GROUP BY "publisher" HAVING COUNT(*) > 1