Re: Date arithmitic in SQL

[Jeff Young <cooljeff913@xxxxxxxxx>]

Vern,
Thanks for the example.
This was a one time fix for a file that got out of sync.

I appreciate all the help and suggestions from all who responded.

Thanks,
 
Jeff Young 
Sr. Programmer Analyst
IBM -e(logo) server Certified Systems Exper - iSeries Technical Solutions V5R2 
IBM  Certified Specialist- e(logo) server i5Series Technical Solutions Designer V5R3
IBM  Certified Specialist- e(logo)server i5Series Technical Solutions Implementer V5R3 
  
 






________________________________
From: Vern Hamberg <vhamberg@xxxxxxxxxxx>
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Sent: Tuesday, November 18, 2008 4:34:32 PM
Subject: Re: Date arithmitic in SQL

Sure - once you have a true date value, use the plus sign (+) followed 
by a number and the word 'days'.

Now if you have a numeric representation, it gets harder. You have to 
convert that to a true date, probably by using combination of substrings 
and char() functions, then once you have the new date, convert it back 
to that number.

Or see if Alan Campin's date UDF can help you - http://www.think400.dk 
is the link, I think. Dig into the downloadable stuff there.

V5R3 might not have all the casting functionality to let you convert 
from a character string back to a number - I forget.

OK - ran a test - yes, V5R3 can do this - but it is ugly - heh! Check 
this out - it adds 5 days to December 13, 2001, assuming MMDDYYYY in 
your "date" field. Change the substring starting values if the format is 
different.

SELECT decimal(replace(char(date(substr(char(12132001), 1, 2) || '/' || 
substr(char(12132001), 3, 2) || '/' || substr(char(12132001), 5, 4)) + 5 
days,usa), '/', '')) FROM sysibm/sysdummy1

It goes without saying, you are probably better off with a UDF

Jeff Young wrote:
> Is there a way to add or subtract a duration (# of days) to a Date field in SQL.
> What I have is a field containing a numeric representation of a date in a file.
> I want to use SQL to increment that field by a specific value.
>
> I am using a V5R3 system.
>
>
> Thanks,
>   
> Jeff Young 
> Sr. Programmer Analyst
> IBM -e(logo) server Certified Systems Exper - iSeries Technical Solutions V5R2 
> IBM  Certified Specialist- e(logo) server i5Series Technical Solutions Designer V5R3
> IBM  Certified Specialist- e(logo)server i5Series Technical Solutions Implementer V5R3 
>