RE: SQL update make fields match

["Jeff Crosby" <jlcrosby@xxxxxxxxxxxxxxxx>]

> Jeff,
> 
> Depends on what percentage need updating..
> 
> If 10%, the yes it would (probably) be better to only update 
> the ones that need it.
> If 90%, the it would be (probably) be better to update all of them.

OK, that makes sense.  That's how I would expect it in RPG land.

> As far as checking first, here's an example:
> UPDATE IMIMSG
>   SET IMIMSG.IMACRC = (SELECT DMITMMST.ACREC
>                        FROM DMITMMST
>                        WHERE DMITMMST.ITNBR = IMIMSG.IMITEM
>                        )
>   where imimsg.imitem in (select imimsg.imitem
>                           from imimsg, dmitmmst
>                           where imimsg.imitem = dmitmmst.itnbr
>                             and imimsg.imacrc <> dmitmmst.acrec
>                           )

You lost me there.  I append this where clause to my existing statement?  Or
replace the existing where clause?

The SQL book I ordered just arrived.  I hope some solid reading will clear
some of this up.  Thanks again for all your help.