From: | Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> |
---|---|
To: | Ron <ronljohnsonjr(at)gmail(dot)com>, pgsql-general(at)lists(dot)postgresql(dot)org |
Subject: | Re: "two time periods with only an endpoint in common do not overlap" ??? |
Date: | 2021-10-15 13:59:01 |
Message-ID: | 98ea7ea3-38ac-d145-e668-803e5ea14de7@aklaver.com |
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Lists: | pgsql-general |
On 10/15/21 06:52, Ron wrote:
> On 10/14/21 7:02 PM, Adrian Klaver wrote:
> [snip]
>> or the third example in the docs:
>>
>> SELECT (DATE '2001-02-16', DATE '2001-12-21') OVERLAPS
>> (DATE '2001-10-30', DATE '2002-10-30');
>> Result: true
>> SELECT (DATE '2001-02-16', INTERVAL '100 days') OVERLAPS
>> (DATE '2001-10-30', DATE '2002-10-30');
>> Result: false
>> SELECT (DATE '2001-10-29', DATE '2001-10-30') OVERLAPS
>> (DATE '2001-10-30', DATE '2001-10-31');
>> Result: false
>
> Why /don't/ they overlap, given that they share a common date?
Per the docs:
https://www.postgresql.org/docs/current/functions-datetime.html
" Each time period is considered to represent the half-open interval
start <= time < end, unless start and end are equal in which case it
represents that single time instant."
Which I read as
(DATE '2001-10-29', DATE '2001-10-30') ends at '2001-10-29'
and
(DATE '2001-10-30', DATE '2001-10-31') starts at DATE '2001-10-30'
so no overlap.
>
> --
> Angular momentum makes the world go 'round.
--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com
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