您可以用途：

SELECT TRUNC(MONTHS_BETWEEN(SYSDATE, MAX(birthdate))/12) AS age
FROM   employees;

其中，对于示例数据：

CREATE TABLE employees ( id, birthdate ) AS
-- First employee will be 20 tomorrow
SELECT 1, ADD_MONTHS(TRUNC(SYSDATE), -20*12) + INTERVAL '1' DAY FROM DUAL UNION ALL
-- Second employee is 25 today
SELECT 2, ADD_MONTHS(TRUNC(SYSDATE), -25*12) FROM DUAL;

输出：
| 年龄|
| - ------|
| 十九|
fiddle

如果你不太关心月份和日期，一个简单的选择是从系统日期和最小的生日中提取year，然后减去它们：
样本数据：

SQL> with employees (employeeid, lastname, birthdate) as
  2    (select 1, 'Little', date '2015-08-25' from dual union all  --> youngest
  3     select 2, 'Foot'  , date '2000-11-13' from dual
  4    )

质询：

5  select extract(year from sysdate) - extract(year from max(birthdate)) as age
  6  from employees;

       AGE
----------
         8

SQL>

你可以从SYSDATE中减去MAX（生日）--结果是天数，所以你应该把天转换成年。

WITH 
    tbl AS 
        (
            select 
                to_date('09-09-1965', 'dd-mm-yyyy') birthdate,
                SYSDATE my_sysdate
            from   dual
        )
SELECT FLOOR((my_sysdate - MAX(birthdate))/ 365) "YEARS_OLD" From tbl

  YEARS_OLD
-----------
         57