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'。
* - identifier;
          * - constant expression with string result, like currentDatabase();
          * -- string literal as specific case;
          * - empty string means 'use default database from cluster'.
          *
          * Distributed engine also supports SETTINGS clause.
          */
        ASTs & engine_args = args.engine_args;
        if (engine_args.size() < 3 || engine_args.size() > 5)
            throw Exception(
                "Storage Distributed requires from 3 to 5 parameters - "
                "name of configuration section with list of remote servers, "
                "name of remote database, "
                "name of remote table, "
                "sharding key expression (optional), "
                "policy to store data in (optional).",
                ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
        String cluster_name = getClusterNameAndMakeLiteral(engine_args[0]);
        const ContextPtr & context = args.getContext();
        const ContextPtr & local_context = args.getLocalContext();
        engine_args[1] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[1], local_context);
        engine_args[2] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[2], local_context);
        String remote_database = engine_args[1]->as<ASTLiteral &>().value.safeGet<String>();
        String remote_table = engine_args[2]->as<ASTLiteral &>().value.safeGet<String>();
        const auto & sharding_key = engine_args.size() >= 4 ? engine_args[3] : nullptr;
        String storage_policy = "default";
        if (engine_args.size() >= 5)
        {
            engine_args[4] = evaluateConstantExpressionOrIdentifierAsLiteral(engine_args[4], local_context);
            storage_policy = engine_args[4]->as<ASTLiteral &>().value.safeGet<String>();