Date: Tue, 9 Jul 2019 11:48:25 -0400
From: Bruce Momjian <bruce@momjian.us>
To: David Harper <adh@sanger.ac.uk>
Cc: pgsql-docs@lists.postgresql.org
Subject: Re: Ambiguous language in Table 8.13. Special Date/Time Inputs [EXT]
Message-ID: <20190709154825.egarmx2s5jyvft4e@momjian.us>
References: <156258047907.1181.11324468080514061996@wrigleys.postgresql.org>
 <20190709033234.ytbltfn25h5wvdbd@momjian.us>
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On Tue, Jul  9, 2019 at 09:14:27AM +0100, David Harper wrote:
> > Uh, I believe midnight is always the start of the day.
> 
> The U.S. National Institute of Standards and Technology (NIST) deprecates the term “midnight” as ambiguous and recommmends the use of 24-hour clock notation:
> 
> ===== BEGIN QUOTE =====
> When someone refers to "midnight tonight" or "midnight last night" the reference of time is obvious. However, if a date/time is referred to as "at midnight on Friday, October 20th" the intention could be either midnight the beginning of the day or midnight at the end of the day.
> 
> To avoid ambiguity, specification of an event as occurring on a particular day at 11:59 p.m. or 12:01 a.m. is a good idea, especially legal documents such as contracts and insurance policies. Another option would be to use 24-hour clock, using the designation of 0000 to refer to midnight at the beginning of a given day (or date) and 2400 to designate the end of a given day (or date).
> ===== END QUOTE =====
> 
> Source:
> 
> https://www.nist.gov/pml/time-and-frequency-division/times-day-faqs
> 
> > I think 00:00:00 looks awkward.
> 
> Perhaps, but in technical documentation, accuracy should have priority over aesthetics, surely?
> 

Yes, I see what you mean now.  How is this patch, which uses "zero
hour"?

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +

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diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index 35ecd48ed5..3b5b8a65d0 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -2174,17 +2174,17 @@ January 8 04:05:06 1999 PST
          <row>
           <entry><literal>today</literal></entry>
           <entry><type>date</type>, <type>timestamp</type></entry>
-          <entry>midnight today</entry>
+          <entry>midnight (zero hour) today</entry>
          </row>
          <row>
           <entry><literal>tomorrow</literal></entry>
           <entry><type>date</type>, <type>timestamp</type></entry>
-          <entry>midnight tomorrow</entry>
+          <entry>midnight (zero hour) tomorrow</entry>
          </row>
          <row>
           <entry><literal>yesterday</literal></entry>
           <entry><type>date</type>, <type>timestamp</type></entry>
-          <entry>midnight yesterday</entry>
+          <entry>midnight (zero hour) yesterday</entry>
          </row>
          <row>
           <entry><literal>allballs</literal></entry>

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