SQL, Group by one column

Question

I have data like this :

 ID              VERSION        SEQUENCE 
 -------------- -------------- ---------------
  01-001         01            001          
  01-002         01            002          
  02-002         02            002

And I want to select only the higher version for each sequence in order to have a result like this :

 ID              VERSION        SEQUENCE 
 -------------- -------------- ---------------
  01-001         01            001             
  02-002         02            002

I think the request should contains a group by on Sequence, but I can't manage to make it work

Can someone help ?

Answer 1

So filter to include only those rows where the version is the highest version in it's sequence

Select id, version, sequence
From DataTable dt
where version =
    (Select Max(version)
     From DataTable 
     where Sequence = dt.Sequence)

Answer 2

using a Common Table Expression you could:

with HighestSequence(ID,MaxSequence)
as 
(
   select id, max(Sequence)
   from table
   group by ID
)

select t.*
from table t
inner join HighestSequence hs
on t.id = hs.id
and t.sequence = hs.sequence

Answer 3

You didn't specify your DBMS so this is ANSI SQL:

select id, version, sequence
from (
  select id, version, sequence,
         row_number() over (partition by id order by sequence) as rn
  from the_table
) t
where rn = 1
order by id;