WITH x AS ( 
SELECT empno, ename, job, sal, hiredate, MAX(sal)OVER(ORDER BY hiredate) max_sal 
FROM scott.emp  
WHERE job!='PRESIDENT' 
), y AS ( 
SELECT empno, ename, job, sal, hiredate start_date, max_sal,  
       LEAD(hiredate) OVER(ORDER BY hiredate) end_date 
FROM x 
WHERE sal=max_sal 
), z AS ( 
SELECT y.*, LEAST(end_date, date'1981-12-31')-start_date days_on_top, 
RANK()OVER(ORDER BY LEAST(end_date, date'1981-12-31')-start_date DESC) rk 
FROM y 
WHERE EXTRACT(YEAR FROM start_date) IN (1980, 1981)  
) 
SELECT empno,ename,job,sal, start_date "Start Date", 
       end_date "End Date", days_on_top	"Days on Top" 
FROM z 
WHERE rk=1

WITH x AS ( 
SELECT empno, ename, job, sal, hiredate, MAX(sal)OVER(ORDER BY hiredate) max_sal 
FROM scott.emp  
WHERE job!='PRESIDENT' 
  AND hiredate>=date'1980-01-01'  
), y AS ( 
SELECT empno, ename, job, sal, hiredate start_date,  
       LEAST(date'1981-12-31', LEAD(hiredate) OVER(ORDER BY hiredate)) end_date 
FROM x 
WHERE sal=max_sal 
) 
SELECT empno,ename,job,sal, start_date "Start Date", 
       end_date "End Date", end_date-start_date "Days on Top" 
FROM y 
WHERE end_date-start_date=(SELECT MAX(end_date-start_date) FROM y)

WITH e AS ( 
SELECT empno, ename, sal, job, LEAST(hiredate, date'1981-12-31') hiredate,  
       MAX(sal)OVER(ORDER BY hiredate) max_sal 
FROM scott.emp 
WHERE hiredate>=date'1980-01-01'  
  AND job!='PRESIDENT' 
), x AS ( 
SELECT empno, ename, job, sal, hiredate,  
       NVL(LEAD(hiredate)OVER(ORDER BY hiredate),date'1981-12-31')-hiredate diff, 
       NVL(LEAD(hiredate)OVER(ORDER BY hiredate),date'1981-12-31') end_date 
FROM e 
WHERE sal=max_sal 
) 
SELECT empno, ename, job, sal, hiredate "Start Date", 
       end_date "End Date", diff "Days on Top" 
FROM x 
MODEL RETURN UPDATED ROWS 
DIMENSION BY (empno, RANK()OVER(ORDER BY diff DESC) rk) 
MEASURES(ename,job,sal, hiredate, end_date, diff, 0 dummy) 
RULES(dummy[ANY, 1]=1)

WITH x AS ( 
SELECT empno, ename, job, sal, hiredate, MAX(sal)OVER(ORDER BY hiredate) max_sal 
FROM scott.emp  
WHERE job!='PRESIDENT' 
), y AS ( 
SELECT empno, ename, job, sal, hiredate start_date,  
       LEAST(date'1981-12-31', LEAD(hiredate) OVER(ORDER BY hiredate)) end_date, 
       LEAST(date'1981-12-31', LEAD(hiredate) OVER(ORDER BY hiredate))-hiredate days_top 
FROM x 
WHERE sal=max_sal 
ORDER BY days_top DESC NULLS LAST, hiredate 
) 
SELECT * 
FROM y 
WHERE ROWNUM=1