Query not showing out put

Question

i am writing SQL lines they are part of my stored procedure there is not any error in this but this not
showing me any result but giving me message anonymous block completed
set serveroutput  on
declare
var varchar(50);
re varchar(50);
begin
var:='zoheb123456789';
re :=length(var);
if re!='' then
dbms_output.put_line(var);
dbms_output.put_line(re);
else
dbms_output.put_line('no');
end if;
end;please help me
Edited by: BluShadow on 14-Feb-2011 08:53
to show code tags and convert <> to != for the forums

Answer 1

sql> declare
  2    var varchar(50);
  3    re  varchar(50);
  4  begin
  5    var:='zoheb123456789';
  6    re :=length(var);
  7    if re != ''
  8    then
  9      dbms_output.put_line(var);
10      dbms_output.put_line(re);
11    else
12      dbms_output.put_line('no');
13    end if;
14* end;
15  /
no
PL/SQL procedure successfully completed.As you can see, it works in sql*plus.
The result, "no" may not be what you expect. The reason for this is the handling of the empty string, in
if re != ''Oracle translates '' to null:
if re != nullThis will always evaluatie to false (null checking should be of course be done with IS [NOT] NULL).
BTW: why is re varchar2 anyway? It is assigned a numeric value, so changing it into numeric would be better. And you would avoid the faulty null checking.