How to add number of days in postgresql datetime

Question

I have a following table projects.

id title        created_at               claim_window 1  Project One  2012-05-08 13:50:09.924  5 2  Project Two  2012-06-01 13:50:09.924  10 

A) I want to find the deadline with calculation deadline = created_at + claim_window(No. of days).

Something like following.

id title        created_at               claim_window  deadline 1  Project One  2012-05-08 13:50:09.924  5             2012-05-13 13:50:09.924 2  Project Two  2012-06-01 13:50:09.924  10            2012-06-11 13:50:09.924 

B) I also want to find the projects whose deadline is gone

id title        created_at               claim_window  deadline 1  Project One  2012-05-08 13:50:09.924  5             2012-05-13 13:50:09.924 

I try something like following.

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

But for some reason it is not working.

Answer 1

This will give you the deadline :

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

Alternatively the function make_interval can be used:

select id,          title,        created_at + make_interval(days => claim_window) as deadline from projects 

To get all projects where the deadline is over, use:

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