WHERE中AS后如何使用关键字

Question

我正在计算会员注册的总年份。我需要 return 结果有多少会员注册超过 5 年，但我在运行代码时遇到错误。

第 3 行显示 "duration" 无效标识符

select floor(months_between(SYSDATE,RegistrationDate)/12) as "Duration"

from member

where duration > 5;

Answer 1

您可以使用子查询：

select *
from
(
    select floor(months_between(SYSDATE,RegistrationDate)/12) as "Duration"
    from member
)
where "Duration" > 5;

How to use the keyword after AS in WHERE