Hur väljer man poster med maximala värden i två kolumner?

Analytiska funktioner är din vän:

SELECT   MAX( year    ) KEEP ( DENSE_RANK LAST ORDER BY year ASC, quarter ASC, message ASC ) AS year,
         MAX( quarter ) KEEP ( DENSE_RANK LAST ORDER BY year ASC, quarter ASC, message ASC ) AS quarter,
         MAX( message ) KEEP ( DENSE_RANK LAST ORDER BY year ASC, quarter ASC, message ASC ) AS message,
         type
FROM     info
GROUP BY type;

SQLFIDDLE