Re: No Documentation for to_char(INTERVAL, mask)

On Tue, Mar 06, 2001 at 09:22:25AM -0800, Josh Berkus wrote:
> Karel,
>
> > The 'interval' version of to_char() isn't implemented -- may be in 7.2
> > (it's high in my TODO list:-)
>
> Grazie. (One of the things I love about PostgreSQL is being able to
> get definitive answers on functionality -- try asking Microsoft an "is
> this implemented?" question!)

:-)

> Given the lack of to_char(interval), I'd like to write a PLPGSQL
> function to fill the gap in the meantime. If you can answer a few
> questions about how interval values work, it would be immensely helpful:
>
> 1. Hours, minutes, and seconds are displayed as "00:00:00". Days are
> displayed as "0 00:00:00". How are weeks, months, and years displayed?
>
> 2. If months have their own placeholder in the Interval data type, how
> many days make up a month? Is it a fixed value, or does it depend on
> the calendar?

A displayed format is external string alternate of a internal number based
form. A interval/timestamp string that you use in SQL is parsed to 'tm'
struct (see man ctime) where has each item like hours, minutes own field.
For some date/time operation is used Julian date (..etc) -- internaly PG
not works with strings for date/time.

I mean is too much difficult write a 'interval' to_char() version in
some procedural language without access to real (internal) form of
'interval'.

Big date/time guru is Thomas (CC:), comments?

Karel

--
Karel Zak <zakkr(at)zf(dot)jcu(dot)cz>
http://home.zf.jcu.cz/~zakkr/

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