diff --git a/backend/migrations/2026_01_29_141057_add_created_date_to_order_items_table.php b/backend/migrations/2026_01_29_141057_add_created_date_to_order_items_table.php
new file mode 100644
index 0000000..daac044
--- /dev/null
+++ b/backend/migrations/2026_01_29_141057_add_created_date_to_order_items_table.php
@@ -0,0 +1,52 @@
+<?php
+
+use Hyperf\Database\Schema\Schema;
+use Hyperf\Database\Schema\Blueprint;
+use Hyperf\Database\Migrations\Migration;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * 为 order_items 表添加 created_date 字段（冗余存储父订单创建时间）
+     * 用于 hypertable 分区键，与 orders 表保持相同的分区策略
+     */
+    public function up(): void
+    {
+        Schema::table('order_items', function (Blueprint $table) {
+            $table->timestampTz('created_date')
+                ->after('platform_order_id')
+                ->comment('订单创建时间（冗余存储，用于分区）');
+        });
+
+        // 从关联的 orders 表填充 created_date
+        Schema::getConnection()->statement('
+            UPDATE order_items
+            SET created_date = orders.created_date
+            FROM orders
+            WHERE order_items.order_id = orders.id
+        ');
+
+        // 设置为非空
+        Schema::table('order_items', function (Blueprint $table) {
+            $table->timestampTz('created_date')->nullable(false)->change();
+        });
+
+        // 添加索引
+        Schema::table('order_items', function (Blueprint $table) {
+            $table->index('created_date', 'order_items_created_date_idx');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('order_items', function (Blueprint $table) {
+            $table->dropIndex('order_items_created_date_idx');
+            $table->dropColumn('created_date');
+        });
+    }
+};