RANK and DENSE_RANK

Hey Guys,

RANK() : function always returns sequential order for each record.
DENSE_RANK() : It returns continuous order for each record.

SELECT empno,
       deptno,
       sal,
       mgr,
       RANK () OVER (PARTITION BY deptno ORDER BY sal) "rank",
       DENSE_RANK() OVER (PARTITION BY deptno ORDER BY sal) "dense rank"    
  FROM emp;

EMPNO	DEPTNO	SAL	MGR	RANK	DENSE RANK
7934	10	1300	7782	1	1
7782	10	2450	7839	2	2
7839	10	5000		3	3
7369	20	800	7902	1	1
7876	20	1100	7788	2	2
7566	20	2975	7839	3	3
7788	20	3000	7566	4	4
7902	20	3000	7566	4	4
7900	30	950	7698	1	1
7521	30	1250	7698	2	2
7844	30	1250	7698	2	2
7654	30	1250	7698	2	2
7499	30	1600	7698	5	3
7698	30	2850	7839	6	4