创建商品价格修改记录表 new创建修改时间

create table price_log(

   id int not null auto_increment primary key,

   product_id int unsigned not null,  

   price decimal(10,2),

   create_time timestamp not null default current_timestamp,

   update_time timestamp not null default current_timestamp on update current_timestamp,

      foreign key(product_id) references product(product_id) on delete cascade on update cascade

   );