Re: Those flippin dates

[Nick_Radich@xxxxxxxxxxxxxx]

Jerry,

I started doing the DS thing also, back on the S/36, and ran some tests 
against it.  I agree that the DS is faster.  Also, like you said, it is 
more understandable at a glance to see what is going on.  You only have to 
do 2 MOVEs and you have your date in the format you want.  And you don't 
have to remember how many zeros and where to put the decimal point in.:-)



Thanx,

Nick



Nick Radich
Sr. Programmer/Analyst
EPC Molding, Inc.
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Toll free  (800) 388-2155  ext. 6683
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nick_radich@xxxxxxxxxxxxxx



Jerry Adams <jerry@xxxxxxxxxxxxxxx> 
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09/05/2007 04:10 PM
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Re: Those flippin dates






Pete,

As you found out, EVAL expressions don't like overflow.  The whole math 
technique was predicated on overflow (i.e., digits flying off into 
neverneverland on both the left (high) and right(low) order sides).  It 
will still work if you change it to:

    MMDDYY   MULT   10000.0001   YYMMDD

But the other options presented are probably more efficient.  I once did 
a test on the /36 of the math technique vs the data structure method and 
the DS method won.  Not too important for interactive stuff, but for 
batch against tons of data it made a big difference.  Plus it's probably 
more understandable to someone who never read or knew about the math 
method ("What the @#$% is that all about?!").


                 * Jerry C. Adams
*IBM System i Programmer/Analyst
B&W Wholesale Distributors, Inc.* *
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Pete Helgren wrote:
> What would be the most expedient way to convert a 6.0 numeric field that 

> represents a date in MMDDYY format to a 6.0 numeric field that 
> represents a date in YYMMDD order?  The resultant numeric is used in an 
> SQL statement comparing it to a numeric (not a date) field.  The old 
> technique of  YYMMDD = MMDDYY * 10000.0001 appears not to work because 
> the program is cranky at runtime about the result field not being large 
> enough.
>
> Since the compare is a numeric I figured that the math would be 
> numeric.  Or, is using a date field and converting it to a numeric host 
> variable for the SQL the way to go?
>
> Pete Helgren