Decimal Data Errors and Embedded SQL

So, here's the deal....

We have a bunch of crappy old RPGIII (really RPGII) style programs that make
up the heart of a software package. The likelihood of replacing/fixing them
any time soon is zero to none. The problem is, as you know,  unlike RPGIV,
RPGIII does not necessarily initialize variables to their base values when
writing/updating a file. So what we end up with, on occasion, are records
that contain numeric fields with invalid data in them.

To compound the problem, and this part REALLY drives me nuts...someone
decided years ago that it was a GOOD DESIGN PRACTICE to store alpha
characters in certain numeric fields.  GAH!

My problems come in when I try to use SQL, either Embedded in an RPG program
or from a VB program on a PC or whatever...I get errors because SQL doesn't
like having invalid data in numeric fields. Imagine that!

I'm sure that this problem is not unique, although it's implementation may
be...:-)

How do you get around Decimal Data Errors and STILL use SQL (Embedded or
otherwise)?

Thanks for any suggestions!
Shannon O'Donnell