alter table table_name modify column_name varchar2(32);
it will do it.
Ok I am not that conversant with oracle,
but in the above statement I beleive that u want me to replace
the table_name and column_name with the actual table name and the
actual column name, if this is the case then, as far as I believe dual is a virtual table and it has just one column so ...?
it would be helpful if u could elaborate more.