select pr from PlatformRelease pr
where pr.unlisted = false
and pr.platformStream.platform.platformType = 'C'
and (pr.platformStream, pr.versionSortable) in
    (
     select pr2.platformStream, max(pr2.versionSortable) from PlatformRelease pr2
         where pr2.platformStream.unlisted = false
         and pr2.unlisted = false
         group by pr2.platformStream
    )
order by pr.versionSortable desc, pr.platformStream.platform.isDefault desc