Re: query by first occurrence in group

[Peter Brawley]

You want the "first" row, but without a defined order that's entirely meaningless. Supposing you want the smallest matriculate value per largest number value per sector, that would be ...

select t.sector, n.maxnum, min(t.matriculate) mat
from tbl t
join (
  select sector, max(number) as maxnum
  from tbl
  group by sector
) n on t.sector=n.sector && t.number=n.maxnum
group by sector, number;