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'。
auto convert_actions_dag = ActionsDAG::makeConvertingActions(pipe.getHeader().getColumnsWithTypeAndName(),
                                                                     header.getColumnsWithTypeAndName(),
                                                                     ActionsDAG::MatchColumnsMode::Name);
        auto actions = std::make_shared<ExpressionActions>(
            convert_actions_dag,
            ExpressionActionsSettings::fromContext(local_context, CompileExpressions::yes));
        pipe.addSimpleTransform([&](const Block & stream_header)
        {
            return std::make_shared<ExpressionTransform>(stream_header, actions);
        });
    }
    auto where_expression = query->as<ASTSelectQuery>()->where();
    if (!where_expression)
        return;
    for (size_t column_index : collections::range(0, header.columns()))
    {
        ColumnWithTypeAndName header_column = header.getByPosition(column_index);
        ColumnWithTypeAndName before_column = before_block_header.getByName(header_column.name);
        
        
        
        if (!header_column.type->equals(*before_column.type.get()) && processed_stage > QueryProcessingStage::FetchColumns)
        {
            NamesAndTypesList source_columns = metadata_snapshot->getSampleBlock().getNamesAndTypesList();
            auto virtual_column = *getVirtuals().tryGetByName("_table");
            source_columns.emplace_back(NameAndTypePair{virtual_column.name, virtual_column.type});
            auto syntax_result = TreeRewriter(local_context).analyze(where_expression, source_columns);
            ExpressionActionsPtr actions = ExpressionAnalyzer{where_expression, syntax_result, local_context}.getActions(false, false);
            Names required_columns = actions->getRequiredColumns();
            for (const auto & required_column : required_columns)