using RANK or DENSE_RANK in Oracle 10g

SELECT sqthree.employeeid,
       sqthree.employeename, 
       to_char(sqthree.Topprofit,'$99,999.99') as TopProfit
FROM (
        /* #3 - select First and Second position */
        SELECT sqtwo.employeeid, sqtwo.employeename, sqtwo.TopProfit
        FROM (
                /* #2 - order the innermost */
                SELECT innermost.employeeid, innermost.employeename, innermost.TopProfit
                FROM (
                        /* #1 - innermost subquery */
                        SELECT s.empid employeeid,
                           s.ename employeename,
                           /* used NVL here */
                           NVL(SUM(i.price * oi.qty),0) - NVL(s.salary,0) TopProfit
                        FROM salespersons s
                        LEFT JOIN orders o ON s.empid = o.empid
                        LEFT JOIN orderitems oi ON o.orderid = oi.orderid
                        LEFT JOIN inventory i ON oi.partid = i.partid
                        GROUP BY s.empid, s.ename, s.salary
                      ) innermost
                ORDER BY TopProfit DESC
            ) sqtwo
      
        WHERE ROWNUM = 1
        ORDER BY TopProfit DESC
     ) sqthree

WHERE ROWNUM = 1 and sqthree.Topprofit is not null;