Search notes:

ORA-01723: zero-length columns are not allowed

The following create table statement throws the error ORA-01723: zero-length columns are not allowed:

create table
   tq84_ora_01723 as
select
   null as n
from
  dual;

It is possible to create a table with initial null values if these are cast into a datatype:

create table
   tq84_ora_01723 as
select
   cast(null as varchar2(100)) as n
from
  dual;

See also