Re: BUG #1518: Conversions to (undocumented) SQL year-month and

>>>>> "Bruce" == Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:

Bruce> OK, here are the TODO items I have created:

Bruce> * Add support for ANSI time INTERVAL syntax, INTERVAL '1
Bruce> 2:03:04' DAY TO SECOND

Bruce> * Add support for ANSI date INTERVAL
Bruce> syntax, INTERVAL '1-2' YEAR TO MONTH

You may as well use the correct ANSI terminology:

* Add support for ANSI day-time INTERVAL syntax, INTERVAL '1
2:03:04' DAY TO SECOND

* Add support for ANSI year-month INTERVAL syntax, INTERVAL '1-2'
YEAR TO MONTH

Bruce> * Process mixed ANSI/PG INTERVAL syntax, and round value
Bruce> to requested precision

Never round, I think. Throwing away precision should be an exception,
unless the discarded fields were zero.

Bruce> Interpret INTERVAL '1 year' MONTH as CAST (INTERVAL '1
Bruce> year' AS INTERVAL MONTH), and this should return '12
Bruce> months'

Bruce> Is this sufficient?

You also need to make EXTRACT do the right thing.

eg EXTRACT (MONTH FROM INTERVAL '1-1' YEAR TO MONTH) => 1

but

EXTRACT (MONTH FROM INTERVAL '13' MONTH) => 13

Ditto for day-time intervals, of course.

I'll have a think about if there's anything else...

-roy