The following bug has been logged on the website:
Bug reference: 14527
Logged by: John Cantin
Email address: jcantin(at)strategicfuse(dot)com
PostgreSQL version: 9.3.6
Operating system: centos 7
Description:
Postgres seems to define calendar week differently depending on the function
called.
The extract function shows '2017-1-1' as week 52 but the to_char function
shows it as 1
select extract('week' from '2017-1-1'::date) as week
select to_char('2017-1-1'::date,'ww')