diff --git a/database/migrations/2026_01_15_195530_alter_clients_table_collation.php b/database/migrations/2026_01_15_195530_alter_clients_table_collation.php
new file mode 100644
index 0000000..469be8e
--- /dev/null
+++ b/database/migrations/2026_01_15_195530_alter_clients_table_collation.php
@@ -0,0 +1,24 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class extends Migration
+{
+    /**
+     * clients 테이블 Collation을 utf8mb4_unicode_ci로 변경
+     * (다른 테이블과 통일하여 UNION 쿼리 호환성 확보)
+     */
+    public function up(): void
+    {
+        DB::statement('ALTER TABLE clients CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci');
+    }
+
+    /**
+     * 롤백 시 원래 Collation으로 복원
+     */
+    public function down(): void
+    {
+        DB::statement('ALTER TABLE clients CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci');
+    }
+};
\ No newline at end of file