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Re: [patch #5637] Implement DATESUM, DATEDIFF expression function
From: |
Ben Pfaff |
Subject: |
Re: [patch #5637] Implement DATESUM, DATEDIFF expression function |
Date: |
Sat, 16 Dec 2006 12:22:32 -0800 |
User-agent: |
Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) |
"Daniel E WILLIAMS" <address@hidden> writes:
> Thanks. I think the arguments are backwards in the function call, if you are
> trying for SPSS compatibility. SPSS uses the format DATEDIFF(last_date,
> first_date, unit). I think you implemented DATEDIFF(first_date, last_date,
> unit). I tried to find this in the code to fix myself, but am stumped. Can
> you tell me where to look? Thanks.
Well, that's an embarrassing bug. I completely mis-read the SPSS
documentation, and I don't have an SPSS 15 license so I couldn't
check it.
I checked in your fix.
Would you mind checking a couple of things for me where the SPSS
documentation is ambiguous? First: does time of day count for
DATEDIFF? That is, is the difference in years between 1 Jan 2004
at 2pm and 1 Jan 2005 at 1pm zero years or one year?
Second: does time of day count for DATESUM? That is, is 1 Jan
2004 at 1pm, plus one month, equal to 1 Feb 2004 at 1pm or at
midnight?
--
"I was born lazy. I am no lazier now than I was forty years ago,
but that is because I reached the limit forty years ago. You can't
go beyond possibility."
--Mark Twain