How to find the record in a table that contains the maximum value?

Question

Although this question looks simple, it is kind of tricky.

I have a table with the following columns:

table A:
  int ID
  float value
  datetime date         


        

Answer 1

This is just what analytic functions were made for:

select group,
       id,
       value
from   (
       select group,
              id,
              value,
              date,
              max(date) over (partition by group) max_date_by_group
       from A
       )
where  date = max_date_by_group