So, <> '' is same as <> NULL which is useless in PL/SQL, am I right?
Michel Cadot <micadot_at_netcourrier.com> wrote:
: No, you can't use that because " is not '' " is not
: part of the SQL syntax, you have to use " is not null ".
: When i say '' is the same as null, i just mean that ''
: indicates a null string as the keyword null does.
: See:
: v734>l
: 1 declare
: 2 begin
: 3 if '' is not null then
: 4 dbms_output.put_line(''''' is not null');
: 5 else
: 6 dbms_output.put_line(''''' is null');
: 7 end if;
: 8* end;
: v734>/
: '' is null
: PL/SQL procedure successfully completed.
: Norris a écrit dans le message <7rlhi1$77u2_at_imsp212.netvigator.com>...
:>If '' is the same as NULL then can I use:
:>" is not '' " instead of " is not null " ?
:>
:>Michel Cadot <micadot_at_netcourrier.com> wrote:
:>: You have to change <> '' to is not null.
:>: As a matter of fact, '' is the same as NULL in PL/SQL
:>: so <> '' cannot be true and else part is execute.
:>
:>: v734>l
:>: 1 declare
:>: 2 abc varchar2(1);
:>: 3 begin
:>: 4 abc := 'a';
:>: 5 if abc is not null then
:>: 6 dbms_output.put_line(abc||' <> empty');
:>: 7 else
:>: 8 dbms_output.put_line(abc||' = empty');
:>: 9 end if;
:>: 10* end;
:>: v734>/
:>: a <> empty
:>
:>: PL/SQL procedure successfully completed.
:>
:>
:>: Norris a écrit dans le message <7rl8s6$4qs$1_at_adenine.netfront.net>...
:>:>I am writing some simple PL/SQL , but I cannot intepret the result:
:>:>
:>:>set serveroutput on
:>:>declare
:>:>abc varchar2(1);
:>:>begin
:>:>abc := 'a';
:>:>if abc <> '' then
:>:> dbms_output.put_line(abc||' <> empty');
:>:>else
:>:> dbms_output.put_line(abc||' = empty');
:>:>end if;
:>:>end;
:>:>
:>:>
:>:>The Result
:>:>----------
:>:>ServerOutput ON
:>:>Statement processed.
:>:>a = empty
:>:>
:>:>
:>:>
:>:>
:>:>
:>:>
:>:>--
:>:>- Have several nice days...
:>:>- Opinions are mine and do not necessarily reflect those of the Corp.
:>:>http://www.ntfaq.com
:>:>http://www.cyberport.com/~tangent/programming/winsock/
:>
:>
:>
:>--
:>--
:>http://www.washington.edu/pine/faq/
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Received on Tue Sep 14 1999 - 22:26:06 CDT
