A.主鍵 B.外鍵 C.默認(rèn)值 D.UNIQUE約束
A.只是修改 B.只是插入 C.只是刪除 D.修改、插入、刪除
A.SELECT quantity,UnitPrice FROM sales B.SELECT quantity,UnitPrice,quantity+UnitPrice AS totalPrices FROM sales C.SELECT quantity,UnitPrice,quantity*UnitPrice AS totalPrices FROM sales D.SELECT quantity,UnitPrice,sum(quantity*UnitPrice) AS totalPrice FROM sales