We have a table with TEXT column that may have non-printable
characters. I.e. ascii 0 thru 31 and ascii > 254. I want to
run select SQL in Sybase central that will bring result set
with all non-printable characters replaces as '?' e.g.

SELECT replace(TEXTColumn, regexp,'?') from TABLE
Here regexp is a range of ascii 0 thru 31 and ascii > 254
Can you provide simple and efficient solution to achieve