RE: Embedded SQL update a field based on difference of totals in2otherfiles

Jeff,

You may be correct, but I thought your coalesce would take care of that.

To be honest, I always have to play around a little bit with these types
of statements to get what I want. <grin>

The one gotcha for these types of update statements is that you have to
account for no records being returned, ie. the subselect returns NULL.
If the field you are updating is not NULL capable, then you'll get an
error when you try and run the statement.

Again, from a quick look, I thought the way you had the coalesce would
take care of that.


Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
  

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx 
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Jeff Crosby
Sent: Monday, September 11, 2006 3:27 PM
To: 'RPG programming on the AS400 / iSeries'
Subject: RE: Embedded SQL update a field based on difference 
of totals in2otherfiles

Try this:

ActSQL = 'Update DMVDRMST z +
                 Set z.AMDUE = +
                 Coalesce((Select Sum(i.INVAM) - Sum(p.PAYAM) +
                           From DMVDRMST v +
                             Left Outer Join +
                           VAINVWK i On v.VNDNR = i.VNDNR +
                             Left Outer Join +
                           VAPAYWK p On v.VNDNR = p.VNDNR), +
                           Cast(0.00 as Decimal(7,2))) +
                           where z.vndnr = v.vndnr';

You have to tie a record from the updated file to the 
subselect.  I'm doing that here with the where z.vndnr = 
v.vndnr.  Note that I change to correlation name on the 
update file from v to z so not to confuse it with the 
DMVDRMST file in the subselect.

This would be a simpler form:
ActSQL = 'Update DMVDRMST v +
                 Set v.AMDUE = +
                 Coalesce((Select Sum(i.INVAM) - Sum(p.PAYAM) +
                           from VAINVWK i +
                             Left Outer Join +
                           VAPAYWK p On v.VNDNR = p.VNDNR), +
                           Cast(0.00 as Decimal(7,2)))
                           where v.VNDNR = i.VNDNR';

You shouldn't(?) need the DMVDRMST file in there twice.

Regarding the simpler one, what about the situation where there are no
transactions for a vendor?  AMDUE should be set to zero.  
Since there's no
"Left Outer Join" from DMVDRMST to anything, won't some records be
untouched?

-- 
Jeff Crosby
Dilgard Frozen Foods, Inc.
P.O. Box 13369
Ft. Wayne, IN 46868-3369
260-422-7531

The opinions expressed are my own and not necessarily the 
opinion of my
company.  Unless I say so.


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