(SQL) problems during select (QRY2283)

Hello everyone.

Ok, I have the following problem:

FCTCTP it's  a large, very old file still maintained by very old programs
out there in the production system.
For a new program I'm working at I need to check against this file for few
things before printing a suscint report.

I am writing the program in SQLRPGLE, and before I actually start coding the
RPG part I test all the SQL code until I get the desired results.

But, when I do somthing like "SELECT * FROM CONTAF/FCTCTP WHERE ANOVTO >=
2006", I find that not everything is pretty.
Theoretically, ANOVTO is a packed(4,0). But, one or two of these old
programs that no one really knows who wrote are inserting blanks where 0's
(or any other number) should go, and when the SQL gets to about 500000
records it dies with the error code QRY2283. Checking the pf member I see
that after that record having that situation is not unusual, with many times
ANOVTO being '    ' and not 0000.

How can I get around this? I tried using DEC to 'cast' this field into a
number each time, but the result is the same. Trying to compare against an
empty string fails, because the SQL processor complains (and rightly so)
that the comparison of a string against a packed numeric makes very little
sense.

Any ideas how can I get around this problem using SQL?

I can't touch the file. Can't touch the code that's producing these results,
at least not right now.

Any hint or idea would be very welcome!

Thanks in advance and regards,

I.-