2.创建一个商店的数据，记录客户及购物情况，有以下三个表组成

create table goods(
    goods_id int,
    goods_name varchar(50),
    unit_price decimal(7,2),
    category varchar(50),
    provider varchar(50)
);

create table customer(
    customer_id int,
    name varchar(20),
    address varchar(20),
    sex varchar(5),
    card_id varchar(18)
);


create table purches(
    order_id int,
    customer_id int,
    goods_id int,
    nums int
);