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
A.selectc ompanyname,fax from suppliers where fax is null B.select companyname,fax from suppliers where country in(’China’,’Italy’) C.select companyname,fax from suppliers where country=’China’ or country=’Italy’ D.select companyname,fax from suppliers where fax=null