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Date: Wed, 8 Jan 2025 12:07:09 -0800
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Subject: Re: INTERVAL MINUTE TO SECOND didn't do what I thought it would do
To: Ron Johnson <ronljohnsonjr@gmail.com>,
 pgsql-general <pgsql-general@postgresql.org>
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From: Adrian Klaver <adrian.klaver@aklaver.com>
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On 1/8/25 11:58 AM, Ron Johnson wrote:
> On Wed, Jan 8, 2025 at 2:43 PM Adrian Klaver <adrian.klaver@aklaver.com 
> <mailto:adrian.klaver@aklaver.com>> wrote:
> 

>      > I'd hoped that ::INTERVAL MINUTE TO SECOND would do the trick, but
>      > MINUTE TO SECOND seems to be ignored.
> 
>       From here:
> 
>     https://www.postgresql.org/docs/current/datatype-datetime.html#DATATYPE-INTERVAL-INPUT <https://www.postgresql.org/docs/current/datatype-datetime.html#DATATYPE-INTERVAL-INPUT>
> 
>     "Also, field values “to the right” of the least significant field
>     allowed by the fields specification are silently discarded. For
>     example,
>     writing INTERVAL '1 day 2:03:04' HOUR TO MINUTE results in dropping the
>     seconds field, but not the day field."
> 
> 
> I read that, but it did not mention that the day values are retained.

I suggest reading the entire section(8.5.4. Interval Input) as well as 
8.5.5. Interval Output.

> 
>      >
>      > Is there cast magic that does what I want?
> 
>     The only way I can think of extract the epoch from the interval and
>     pass
>     to a function that builds what you want.
> 
> 
> I was afraid of that.  Must decide if it's worth the time.
>
If you don't mind decimal minutes, a quick and dirty solution is:

select extract(epoch from (now() - '2025-01-07 14:15:32'::timestamptz)) 
/ 60;

1301.5244606333333333


-- 
Adrian Klaver
adrian.klaver@aklaver.com