Re: PL/SQL: handling of empty string (strange)

stephan schrieb:
> Hi everybody,
>
> I've got this code-sample here which puzzles me:
>
> declare
> s VARCHAR2(1):='S';
> begin
> dbms_output.put_line(s);
> if s!='' then
> dbms_output.put_line('hoppla');
> else
> dbms_output.put_line('ballaballa');
> end if;
> end;
> /
>
> When run the program enters the else-branch. But why - 'S'!='' must
> certainly be true!?

No because the empty string '' is interpreted as NULL. So if you change your code to

if s is NULL then
...

you know why you receive 'ballaballa'.

Try using if length(s) > 0 instead.

HTH, Hermann Received on Thu Mar 11 2004 - 08:54:52 CST