[LEAPSECS] Time math libraries, UTC to TAI

Robert Jones robert at jones0086.freeserve.co.uk
Tue Dec 27 07:34:10 EST 2016


Sorry about the top posting, this one is at the bottom


On 26/12/2016 22:09, Robert Jones wrote:
>
> As a minor note, the SQL standard requires timestamps to be in the 
> format (simplified to ignore timezones, variable precisions, etc) 
> yyyymmddhhmmss.ssssss where it is currently for the implementor to 
> decide how to do the date and time manipulations.
>
> SQL 2008 standard
>
> 4.6.2 Datetimes (extracts)
>
> — TIMESTAMP — contains the <primary datetime field>s YEAR, MONTH, DAY, 
> HOUR, MINUTE, and
> SECOND
>
> A datetime value, of data type TIME WITHOUT TIME ZONE or TIMESTAMP 
> WITHOUT TIME ZONE,
> may represent a local time, whereas a datetime value of data type TIME 
> WITH TIME ZONE or TIMESTAMP
> WITH TIME ZONE represents UTC.
>
> in the SQL 2008 standard see NOTE 101 — Datetime data types will allow 
> dates in the Gregorian format to be stored in the date range 
> 0001–01–01 CE through
> 9999–12–31 CE. The range for SECOND allows for as many as two “leap 
> seconds”. Interval arithmetic that involves leap seconds
> or discontinuities in calendars will produce implementation-defined 
> results.
>
> Robert
>

As a minor note, the SQL standard requires timestamps to be in the 
format (simplified to ignore timezones, variable precisions, etc) 
yyyymmddhhmmss.ssssss where it is currently for the implementor to 
decide how to do the date and time manipulations.

SQL 2008 standard

4.6.2 Datetimes (extracts)

— TIMESTAMP — contains the <primary datetime field>s YEAR, MONTH, DAY, 
HOUR, MINUTE, and
SECOND

A datetime value, of data type TIME WITHOUT TIME ZONE or TIMESTAMP 
WITHOUT TIME ZONE,
may represent a local time, whereas a datetime value of data type TIME 
WITH TIME ZONE or TIMESTAMP
WITH TIME ZONE represents UTC.

in the SQL 2008 standard see NOTE 101 — Datetime data types will allow 
dates in the Gregorian format to be stored in the date range 0001–01–01 
CE through
9999–12–31 CE. The range for SECOND allows for as many as two “leap 
seconds”. Interval arithmetic that involves leap seconds
or discontinuities in calendars will produce implementation-defined results.

Robert



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