create table tbl_values (
  id int unsigned not null primary key,
  `Name` varchar(10),
  `Group` varchar(10),
  `Value` int
);

insert into tbl_values values
(1, 'Pete', 'A', 10),
(2, 'Pete', 'B', 20),
(3, 'John', 'A', 10);

-- 1. Create an expression that builds the columns
set @sql = (
    select group_concat(distinct 
        concat(
            "sum(case when `Group`='", `Group`, "' then `Value` end) as `", `Group`, "`"
        )
    ) 
    from tbl_values
);

-- 2. Complete the SQL instruction
set @sql = concat("select Name, ", @sql, " from tbl_values group by `Name`");

-- 3. Create a prepared statement
prepare stmt from @sql;

-- 4. Execute the prepared statement
execute stmt;