feat(订单服务): 在订单统计查询中添加sku字段

在订单商品统计查询SQL中增加sku字段，以便按商品SKU进行分组统计和展示

src/service/order.service.ts

@@ -1479,7 +1479,7 @@ export class OrderService {
     }
 
     let itemSql = `
-      SELECT os.productId, os.name, SUM(os.quantity) AS totalQuantity, COUNT(DISTINCT os.orderId) AS totalOrders
+      SELECT os.productId, os.name, os.sku, SUM(os.quantity) AS totalQuantity, COUNT(DISTINCT os.orderId) AS totalOrders
       FROM order_sale os
       INNER JOIN \`order\` o ON o.id = os.orderId
       WHERE o.date_paid BETWEEN ? AND ?
@@ -1501,7 +1501,7 @@ export class OrderService {
     }
     itemSql += nameCondition;
     itemSql += `
-      GROUP BY os.productId, os.name
+      GROUP BY os.productId, os.name, os.sku
       ORDER BY totalQuantity DESC
       LIMIT ? OFFSET ?
     `;