**Use case**
mysql repl to clickhouse

**Describe the solution you'd like**
Hope MaterializeMySQL engine can support MySQL prefix index



{
    NamesAndTypesList columns_name_and_type;
    for (const auto & declare_column_ast : columns_define->children)
    {
        const auto & declare_column = declare_column_ast->as<MySQLParser::ASTDeclareColumn>();
        if (!declare_column || !declare_column->data_type)
            throw Exception("Missing type in definition of column.", ErrorCodes::UNKNOWN_TYPE);
        bool is_nullable = true;
        bool is_unsigned = false;
        if (declare_column->column_options)
        {
            if (const auto * options = declare_column->column_options->as<MySQLParser::ASTDeclareOptions>())
            {
                if (options->changes.count("is_null"))
                    is_nullable = options->changes.at("is_null")->as<ASTLiteral>()->value.safeGet<UInt64>();
                if (options->changes.count("is_unsigned"))
                    is_unsigned = options->changes.at("is_unsigned")->as<ASTLiteral>()->value.safeGet<UInt64>();
            }