RE: SQL Update with Join

If you do not identify the connection between the files in both the
select statement following the equal sign and in a where clause the
system will attempt to update every record with every value and this
will cause a null condition to occur. The real purpose is record
selection - the where clause tells the system which record to update,
the equal clause tells it what value to use.


John Arnold
(301) 354-2939


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Peter.Colpaert@xxxxxxxxxxx
Sent: Thursday, January 10, 2008 9:30 AM
To: Midrange Systems Technical Discussion
Subject: RE: SQL Update with Join

John,

I thought the where clause was there to avoid possible null values?

Peter Colpaert
Application Developer
PLI - IT - Kontich, Belgium
-----
Yoda of Borg are we. Futile is resistance, assimilated will you be.
-----



"John Arnold (MFS)" <jarnold@xxxxxxxxxxxxxxxxxxxxxxxxxx>
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10/01/2008 14:56
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Subject
RE: SQL Update with Join






You need to identify the connection between the files both within the
parentheses and without so the following should work.

Update inv
Set inv.feat = (select wcs.feat from wcs where wcs.vnd = inv.vnd and
wcs.mdl = inv.mdl) Where inv.vnd in (select wcs.vnd from wcs where
wcs.mdl = inv.mdl)


John Arnold
(301) 354-2939