Question

我有一张下表projects。

id title        created_at                     claim_window
1  Project One  2012-05-08 13:50:09.924437     5
2  Project Two  2012-06-01 13:50:09.924437     10

A）我想通过计算deadline = created_at + claim_window(No. of days)找到截止日期。

如下所示。

id title        created_at                     claim_window deadline
1  Project One  2012-05-08 13:50:09.924437     5            2012-05-13 13:50:09.924437
2  Project Two  2012-06-01 13:50:09.924437     10           2012-06-11 13:50:09.924437

B]我也想找到截止日期已经消失的项目

id title        created_at                     claim_window deadline
1  Project One  2012-05-08 13:50:09.924437     5            2012-05-13 13:50:09.924437

我尝试了类似的事情。

SELECT * FROM "projects" WHERE (DATE_PART('day', now()- created_at) >= (claim_window+1))

但由于某种原因它无效。

Answer 1

这将为您提供截止日期：

select id,  
       title,
       created_at + interval '1' day * claim_window as deadline
from projects

要获得截止日期结束的所有项目，请使用：

select *
from (
  select id, 
         created_at + interval '1' day * claim_window as deadline
  from projects
) t
where localtimestamp at time zone 'UTC' > deadline

Answer 2

对我来说，我必须将整个区间用单引号而不仅仅是区间的值。

select id,  
   title,
   created_at + interval '1 day' * claim_window as deadline from projects

而不是

select id,  
   title,
   created_at + interval '1' day * claim_window as deadline from projects

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