Re: [RFC] allow 'semester' in functions EXTRACT, DATE_PART, TO_CHAR and so on.

On 15/08/15 11:58, Dickson S. Guedes wrote:
> Hello hackers,
>
> * Description
>
> This patch is a proposal to allow the use of word 'semester' to
> extract it from date in functions like EXTRACT, DATE_PART, etc and
> adds the letter 'S' to format the date output in to_char.
>
> ** Example
>
> SELECT EXTRACT(semester FROM DATE '2015-07-07');
>
> date_part
> -----------
> 2
>
> * Motivation
>
> The term is used in a school or college to represent a half-year.
> Actually it could be evaluated from a date using some math with
> 'quarter' but could not be extracted from date since the API to define
> a "reserved word" for EXTRACT is in the core, rather than in SQL.
>
> * Syntax
>
> I'm using the word 'semester' since it is common in college and school
> but I wondering if it should be other word (like 'halfyear', for
> example)
>
> Is this a feature that worth?
>
> BTW, I'll put this in the commit fest (2015-09).
>
> Thanks!
Note that the start and end points for a semester might well be
different between universities in the Northern & Southern Hemispheres of
this planet- also between institutions in the same hemisphere.

The first semester in 2015 for the University of Auckland begins Monday
2 March 2015:
https://www.auckland.ac.nz/en/for/current-students/cs-academic-information/cs-academic-dates.html

The first semester in 2015 for ANU (Australian National University)
begins Monday 16 February 2015:
http://www.anu.edu.au/directories/university-calendar

So semesters don't appear to align with normal half year boundaries.

Cheers,
Gavin