[NOVICE] Julian date output? - 07-15-2011 , 10:43 PM
I can see how to specify a Julian date, (J7395), but how do I get a "random" date converted to a Julian date? Do I need to do the calculation (from 4713 BC) myself?
On a related note, when taking the difference between two dates, how doI "force" the result to be in days (only)?
Thanks in advance.
Always do right.
This will gratify some people and astonish the rest. - Mark Twain
The truth is rarely pure, and never simple. - Oscar Wilde
Re: [NOVICE] Julian date output? - 07-16-2011 , 06:48 AM
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SELECT TO_CHAR(now(), 'J');
SELECT TO_CHAR(myfield, 'J') FROM mytable;
If you are using this for astronomical purposes, keep in mind that
Postgres flips a Julian day at midnight, not noon!
If you are using this as a way to do arithmetic on dates, there
are much better ways:
the number of days, as an integer, so one way is to simply force
the timestamps to dates first:
SELECT now()::date - '1970-01-01 12:34'::date
Alternatively, you can use the EXTRACT function:
SELECT EXTRACT('days' FROM (now() - '1970-01-01 12:34'::timestamp));
Note the difference in result due to where the rounding occurs.
Greg Sabino Mullane greg (AT) turnstep (DOT) com
End Point Corporation http://www.endpoint.com/
PGP Key: 0x14964AC8 201107160740
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