How to get week start and end date string in PostgreSQL?

Question

I am using PostgreSQL 8.3. I have a table like this:

id        regist_time        result
-----------------------------------
1     2012-07-0         


        

Answer 1

It is

select to_date('2015-07', 'IYYY-IW');

use it in postgres

it will return

2015-02-09