ALTER TABLE `mt_cart`
  CHANGE `NUM` `NUM` DOUBLE (10, 2) DEFAULT 1 NULL COMMENT '数量';

ALTER TABLE `mt_goods`
  CHANGE `STOCK` `STOCK` DOUBLE (10, 2) UNSIGNED DEFAULT 0 NULL COMMENT '库存';

ALTER TABLE `mt_goods`
  CHANGE `INIT_SALE` `INIT_SALE` DOUBLE (10, 2) DEFAULT 0 NULL COMMENT '初始销量';

ALTER TABLE `mt_goods_sku`
  CHANGE `STOCK` `STOCK` DOUBLE (10, 2) DEFAULT 0 NOT NULL COMMENT '库存';

ALTER TABLE `mt_order_goods`
  CHANGE `NUM` `NUM` DOUBLE (10, 2) DEFAULT 0 NOT NULL COMMENT '商品数量';