CREATE TABLE book (book_id DECIMAL, title TEXT, issues DECIMAL, writer TEXT)
CREATE TABLE publication (publication_id DECIMAL, book_id DECIMAL, publisher TEXT, publication_date TEXT, price DECIMAL)

List the writers who have written more than one book.
SELECT writer FROM book GROUP BY writer HAVING COUNT(*) > 1
SELECT "writer" FROM "book" GROUP BY "writer" HAVING COUNT(*) > 1