where子句中的mysql伪列

Question

目前，所有行中的status列为0，startdate至少在now()之前的几天，但以下查询返回空结果集。

     select p.id, (select @days:=(datediff(now(),p.startdate))) as days from poa p 
     where p.status < @days;

我哪里可能出错？

Answer 1

SELECT id , days FROM 
( 
SELECT p.id as id , datediff(now(),p.startdate) as days  , p.status as status 
FROM poa p 
) 
t WHERE t.status < t.days;