Ecshop二次开发添加优惠券系统的代码实现

CREATE TABLE `ecs_coupons` (
  `coupon_id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `coupon_name` varchar(255) NOT NULL,
  `coupon_type` tinyint(3) unsigned NOT NULL COMMENT '1:满减券, 2:折扣券',
  `coupon_value` decimal(10,2) NOT NULL,
  `min_amount` decimal(10,2) NOT NULL,
  `start_time` datetime NOT NULL,
  `end_time` datetime NOT NULL,
  `total_amount` int(10) unsigned NOT NULL,
  `used_amount` int(10) unsigned NOT NULL DEFAULT '0',
  PRIMARY KEY (`coupon_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

if (isset($_POST['coupon_id'])) {
    $coupon_id = intval($_POST['coupon_id']);
    $coupon = $db->getRow("SELECT * FROM ecs_coupons WHERE coupon_id = '$coupon_id' AND start_time <= NOW() AND end_time >= NOW() AND used_amount < total_amount");
    if ($coupon) {
        $order_total = $total['amount'];
        if ($order_total >= $coupon['min_amount']) {
            if ($coupon['coupon_type'] == 1) { // 满减券
                $discount = min($coupon['coupon_value'], $order_total);
            } else { // 折扣券
                $discount = $order_total * ($coupon['coupon_value'] / 100);
            }
            $total['amount'] -= $discount;
            $db->query("UPDATE ecs_coupons SET used_amount = used_amount + 1 WHERE coupon_id = '$coupon_id'");
        }
    }
}