Change the table comment after created the table is not supported now?
Like mysql : ALTER TABLE [tableName] COMMNET [comment]; 
The sql "ALTER TABLE `system`.tables UPDATE Comment='test' WHERE NAME='t1';" also not supported!!!
My version is '21.9.4.35'。
{
    NamesAndTypesList virtuals{{"_database", std::make_shared<DataTypeString>()}, {"_table", std::make_shared<DataTypeString>()}};
    auto first_table = getFirstTable([](auto && table) { return table; });
    if (first_table)
    {
        auto table_virtuals = first_table->getVirtuals();
        virtuals.insert(virtuals.end(), table_virtuals.begin(), table_virtuals.end());
    }
    return virtuals;
}
}