Comment by quesera

Reformatted for readability (indent code blocks with two spaces):

  from tracks
  group album_id (
    sort {-milliseconds}
    take 1
  )

Editorializing:

Data query specification is all about getting the details right. This does not look simpler than the corresponding SQL to me though. All components must be present -- scope, group, limit, order.

SQL, for all its faults, is generally succinct at incorporating the required details. The PRQL sample here is succinct as well, but to me at least, not differentiating.