State the publisher name for publisher ID 877? Calculate its average year to date sales.
publisher id refers to pub_id; publisher name refers to pub_name; average year to date sales = AVG(ytd_sales)
SELECT T2.pub_name, AVG(T1.ytd_sales) FROM titles AS T1 INNER JOIN publishers AS T2 ON T1.pub_id = T2.pub_id WHERE T1.pub_id = '0877' GROUP BY T2.pub_name