Re: DB2 numeric to date conversion

Date tables are popular across multiple versions of SQL across multiple
platform. I'm trying to find out if Kent Milligan or Scott Forstie have
any articles or examples on this with DB2 for i.
Basically you have every possible format of a date in each column for every
date for the next 20 years or so.
real date, CCYYMMDD alpha, CCYYMMDD numeric, CYYMMDD, MMDDYY, etc.
Then you just lookup what you're starting with and what you want.
Select MMDDYY from DateTable where realdate=current date.
or
select MMDDYY_order_date, realdate, orderNumber
from OrderHeader H left outer join datetable D on h.MMDDYY_order_date =
d.mmddyy
In this case, if MMDDYY is bogus then you'd get a null value for realdate.
If null's cross your eyes then you could do something like this
select MMDDYY_order_date, ifnull(realdate, date('1776-07-04'), orderNumber
from OrderHeader H left outer join datetable D on h.MMDDYY_order_date =
d.mmddyy

select MMDDYY_order_date, realdate, orderNumber
from OrderHeader H left outer join datetable D on h.MMDDYY_order_date =
d.mmddyy

On Wed, Nov 8, 2023 at 4:40 AM Dave <dfx1@xxxxxxxxxxxxxx> wrote:

Some very interesting replies!

What is in the date table exactly?

Is there also anything simple to get back to numeric YYYYMMDD from the
date? At present I'm doing something like :
myDate = year(dateCol) * 10000 + month(dateCol) * 100 + day(dateCol)

On Mon, 6 Nov 2023 at 17:45, Dave <dfx1@xxxxxxxxxxxxxx> wrote:

Hello,

I came up with this in order to convert a 8,0 numeric field to a date

that

seems to work. Format is YYYYMMDD so it would be a bit different for most
of you.
Can anyone suggest something to make it easier on the eye? Thanks!

select

date('0001-01-01') +
(int(myDate/10000) - 1) years +
(int(mod(myDate , 10000)/100) - 1) months +
(mod(mod(myDate , 10000), 100) - 1) days
from myFile

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