修正了药品订单详情页，优惠金额错误问题

app/Services/PatientOrderService.php

@@ -647,7 +647,19 @@ class PatientOrderService extends BaseService
         }
 
         // 处理优惠金额
-        $order_product['discount_amount'] = $order_product['amount_total'] + $order_product['logistics_fee'] - $order_product['coupon_amount_total'] - $order_product['payment_amount_total']; // 优惠金额
+        $order_product['discount_amount'] = bcsub(
+                bcsub(
+                    bcadd(
+                        $order_product['amount_total'],
+                        $order_product['logistics_fee']
+                        ,2
+                    ),
+                    $order_product['coupon_amount_total'],
+                    2
+                ),
+                $order_product['payment_amount_total'],
+                2
+        ); // 优惠金额
 
 
         $result = array();