diff --git a/backend/app/services/product_service.py b/backend/app/services/product_service.py
index ee6b1b8..4b04600 100644
--- a/backend/app/services/product_service.py
+++ b/backend/app/services/product_service.py
@@ -2,7 +2,7 @@
 from __future__ import annotations
 import uuid
 from fastapi import HTTPException, status
-from sqlalchemy import select, or_, cast, String, delete, update, func
+from sqlalchemy import select, or_, cast, String, delete, update
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload
 
@@ -473,7 +473,7 @@ async def get_all_products(
         ).subquery()
         ranked = (
             select(TR.task_id, TR.remark, TR.created_at, Task.product_id,
-                   func.row_number().over(
+                   sa_func.row_number().over(
                        partition_by=Task.product_id,
                        order_by=TR.created_at.desc()
                    ).label("rn"))