oracle 函数排名

SQL> SELECT empno,ename,sal,rank() over(ORDER BY nvl(sal,0) DESC) 排序 from emp;
 
EMPNO ENAME            SAL         排序
----- ---------- --------- ----------
    1 zhulei      10000.00          1
    2 zhulei%l    10000.00          1
 7839 KING         5000.00          3
 7788 SCOTT        3000.00          4
 7902 FORD         3000.00          4
 7566 JONES        2975.00          6
 7698 BLAKE        2850.00          7
 7782 CLARK        2450.00          8
 7499 ALLEN        1600.00          9
 7844 TURNER       1500.00         10
 7934 MILLER       1300.00         11
 7521 WARD         1250.00         12
 7654 MARTIN       1250.00         12
 7876 ADAMS        1100.00         14
 7900 JAMES         950.00         15
 7369 SMITH         800.00         16
 
16 rows selected
 
SQL> SELECT empno,ename,sal,dense_rank() over(ORDER BY nvl(sal,0) DESC) 排序 from emp;
 
EMPNO ENAME            SAL         排序
----- ---------- --------- ----------
    1 zhulei      10000.00          1
    2 zhulei%l    10000.00          1
 7839 KING         5000.00          2
 7788 SCOTT        3000.00          3
 7902 FORD         3000.00          3
 7566 JONES        2975.00          4
 7698 BLAKE        2850.00          5
 7782 CLARK        2450.00          6
 7499 ALLEN        1600.00          7
 7844 TURNER       1500.00          8
 7934 MILLER       1300.00          9
 7521 WARD         1250.00         10
 7654 MARTIN       1250.00         10
 7876 ADAMS        1100.00         11
 7900 JAMES         950.00         12
 7369 SMITH         800.00         13
 
16 rows selected