[sql] Finding top 5 within group

Cool SQL trick from Todd. With mods for my own purpose.

SELECT A.dt, A.tokengroup, A.token, A.num
  FROM #tmp1 AS A, #tmp1 AS B
  WHERE A.dt = B.dt
    AND A.tokengroup = B.tokengroup
    AND A.token <> B.token and A.num <>
  GROUP BY A.dt, A.tokengroup, A.token, A.num
  HAVING COUNT(*) <= 5
  ORDER BY A.dt, A.tokengroup, A.token, A.num desc