oracle 如何在 where 条件下使用计算列？
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时间：2020-09-18 20:10:31 来源:igfitidea点击:
How to use a calculated column in where condition?
提问by Sachin Chourasiya
How to use a calculated column in the wherecondition in Oracle 9i?
如何where在Oracle 9i中的条件中使用计算列 ？
I want to use something like
我想使用类似的东西
select decode (:pValue,1,
select sysdate from dual,
select activation_date from account where AcNo = 1234) as calDate
where caldate between startDate and endDate;
回答by Tony Andrews
You can use an in-line view:
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;
回答by R. Genaro
You could select your date from dual and join the results:
您可以从 Dual 中选择您的日期并加入结果：
select *
from <<your table with startDate and endDate columns>> -- Since you ommited the main "from" clause from your statement
, (
select decode( :pValue
, 1, sysdate
, ( select activation_date from account where AcNo = 1234 )
) as calDate
from dual
) c
where c.calDate between startDate and endDate
... -- any other conditions you may need
