Generate Upper and Lowercase Alphanumeric Random String in Oracle

Question

How does one generate an upper and lowercase alphanumeric random string from oracle?

I have used select DBMS_RANDOM.STRING(\'x\', 10) from dual to generate

Answer 1

You can make your own function. This is one option:

create or replace function random_str(v_length number) return varchar2 is
    my_str varchar2(4000);
begin
    for i in 1..v_length loop
        my_str := my_str || dbms_random.string(
            case when dbms_random.value(0, 1) < 0.5 then 'l' else 'x' end, 1);
    end loop;
    return my_str;
end;
/

select random_str(30) from dual;

RANDOM_STR(30)
--------------------------------------------------------------------------------
pAAHjlh49oZ2xuRqVatd0m1Pv8XuGs

You might want to adjust the 0.5 to take into account the different pool sizes - 26 for l vs. 36 for x. (.419354839?). You could also use value() and pass in the start and end range of the character values, but that would be character-set specific.

As to why... do Oracle need a reason? The use of x might suggest that it was originally hexadecimal and was expanded to include all upper-case, without it occurring to them to add a mixed-case version at the same time.