Question

I have a table for contents on a page. The page is divided into sections.
I want to get the last version for each page-section.

Id (int)
Version (int)
SectionID

Id    Version    SectionID    Content
1       1           1           AAA
2       2           1           BBB
3       1           2           CCC
4       2           2           DDD
5       3           2           EEE

I want to get:

Id    Version    SectionID    Content
2       2           1           BBB
5       3           2           EEE

Answer 1

You could use an exclusive self join:

select  last.*
from    YourTable last
left join
        YourTable new
on      new.SectionID = last.SectionID
        and new.Version > last.Version
where   new.Id is null

The where statement basically says: where there is no newer version of this row.

Slightly more readable, but often slower, is a not exists condition:

select  *
from    YourTable yt
where   not exists
        (
        select  *
        from    YourTable yt2
        where   yt2.SectionID = yt.SectionID
                and yt2.Version > yt.Version
        )