SQL Maximum Of Group (latest ten, but only one of each group)

groupedmax.sql

SELECT * 
  FROM mytable
 WHERE idfield IN (
  SELECT MAX(main.idfield)
    FROM mytable AS main
    JOIN (
      SELECT groupfield, MAX(maxfield) maximum
      FROM mytable
      GROUP BY groupfield
      ORDER BY maximum DESC
      LIMIT 10
    ) AS selector
    ON (
      main.groupfield = selector.groupfield
      AND
      main.maxfield = selector.maximum
    )
    GROUP BY main.groupfield
  )
  ORDER BY maxfield DESC