我正在尝试过滤别名列，我知道它在 WHERE 子句中不起作用。 我需要过滤 YEARS >15

Question

select department_id, last_name, round(((sysdate-hire_date)/30)/12, 0) as YEARS
from employees
where YEARS >15;

Answer 1

您不能在WHERE子句中引用别名。 一种选择是简单地重复整个循环表达式：

SELECT department_id, last_name,
       ROUND(((SYSDATE - hire_date) / 30) / 12, 0) AS YEARS
FROM employees
WHERE ROUND(((SYSDATE - hire_date) / 30) / 12, 0) > 15;

Answer 2

一种选择是重复圆形表达式，您也可以使用另一种选择DATEDIFF 。

SELECT department_id, last_name,
       ROUND(((SYSDATE - hire_date) / 30) / 12, 0) AS YEARS
FROM employees 
Where  DATEDIFF(year, hire_date, getdate()) > 15

Answer 3

谢谢各位，我今天早上想出了一个解决方案

select department_id, sum(salary) as "Summary" from employees where round(((sysdate-hire_date)/30)/12, 0)>15 group by department_id order by department_id;

Answer 4

这是正确的代码

select department_id, sum(salary) as "Summary" from employees where round(((sysdate-hire_date)/30)/12, 0)>15 group by department_id order by department_id;