diff --git a/database/migrations/2023_04_12_011330_change_agent_allow_deny_table_comment_field_nullable.php b/database/migrations/2023_04_12_011330_change_agent_allow_deny_table_comment_field_nullable.php
index 816a3217..ef59fdd4 100644
--- a/database/migrations/2023_04_12_011330_change_agent_allow_deny_table_comment_field_nullable.php
+++ b/database/migrations/2023_04_12_011330_change_agent_allow_deny_table_comment_field_nullable.php
@@ -14,10 +14,10 @@ return new class extends Migration
     public function up()
     {
         Schema::table('agent_allowed_family', function (Blueprint $table) {
-            $table->string("comment")->nullable(true)->change();
+            $table->string("comment")->nullable(true)->default(null)->change();
         });
         Schema::table('agent_allowed_exception', function (Blueprint $table) {
-            $table->string("comment")->nullable(true)->change();
+            $table->string("comment")->nullable(true)->default(null)->change();
         });
     }