如何在哪里条件下使用计算列？

Question

如何where在Oracle 9i 的条件中使用计算列 ？

我想用类似的东西

select decode (:pValue,1,
               select sysdate from dual,
               select activation_date from account where AcNo = 1234) as calDate
where caldate between startDate and endDate;

Answer 1

您可以使用内嵌视图:

select calcdate from
(
select startDate, endDate,
       decode (:pValue,1,
               select sysdate from dual,
               select activation_date from account where AcNo = 1234) as calcdate
)
where calcdate between startDate and endDate;