Among the books that were published by Scholastic, how many were written by J.K Rowling?
"J.K Rowling" is the author_name; 'Scholastic' is the publisher_name
SELECT COUNT(*) FROM book AS T1 INNER JOIN publisher AS T2 ON T1.publisher_id = T2.publisher_id INNER JOIN book_author AS T3 ON T3.book_id = T1.book_id INNER JOIN author AS T4 ON T4.author_id = T3.author_id WHERE T2.publisher_name = 'Scholastic' AND T4.author_name = 'J.K. Rowling'