设计题 有一个MySQL数据库store,在store数据库中含有一个销售表sale,用...答:use store;create table sale(id int auto_increment primary key,pm varchar(30) ,price decimal(9,2),num int,sum decimal(11,2));insert into sale(pm,price,num) values ('电视机',1400.00,4);select * from sale;update sale set sum = 0 ;select * from sale where price > 4000...