SELECT CAST(title AS char(20)) AS title, type, price, advance FROM titles WHERE ytd_sales IS NOT NULL ORDER BY type DESC COMPUTE AVG(price), SUM(advance) BY type COMPUTE SUM(price), SUM(advance) 6.2.3 鏁版嵁鎺у埗璇 █(DCL) 鏁版嵁鎺у埗璇 █(DCL)鏄 敤鏉ヨ 缃 垨鑰呮洿鏀规...