Try Below Example :-
---FIND SECONDMAXSAL SALARY
SELECT MAX(ESAL)AS SECONDMAXSAL FROM EMP1 WHERE ESAL NOT IN(SELECT MAX(ESAL) FROM EMP1)
--FIND THIRDMAXSAL SALARY
SELECT MIN(ESAL)AS THIRDMAXSAL FROM EMP1 WHERE ESAL IN(SELECT TOP 3 (ESAL) FROM EMP1 ORDER BY ESAL DESC)