How to isolate single values from multiple records
This kind of formatting should be usually done in the front end, not in SQL. 

You can however get the display you want using window functions, no PL/SQL required.

select case when rn = 1 then alpha_code end as alpha_code,
       beta_code, 
       case when rn = 1 then value end as value
from (
  select alpha_code, beta_code, value, 
         row_number() over (partition by alpha_code order by beta_code) as rn
  from the_table
) 
order by beta_code;


SQLFiddle example: http://sqlfiddle.com/#!4/28ca3/1