TechFAQ

DECLARE
    len number;
    str varchar2(20) := '&str';
    rev_str varchar2(20);
    conchar char(1);

BEGIN
    len := length(str);
    for i in REVERSE 1..len loop
     conchar := substr(str,i,1);
     rev_str := rev_str||conchar;
    end loop;
    dbms_output.put_line('REVERSED STRING IS : '||rev_str);
END;