At other database system, for example, i can use:
select * from table where abc>=def

where abc is an Integer value, def is a varchar which contain '30',
so the system will automatically convert 'def' to integer value for
comparison.

But for DB2, it doesnt seems to do that, so what should i do to
make these kind of comparison works?

thanks,
Desmond

db2 will not convert this for you
you have to make the datatype compatible
or translate integer to char or translate char to integer
where abc=int(def)
or
where char(abc)=def