相关疑难解决方法(0)

我有一张桌子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)我想通过计算找到截止日期deadline = created_at + claim_window(No. of days).

跟随之类的事情.

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过去的项目

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

我尝试下面的事情.

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

但由于某种原因它不起作用.