Descobri a necessidade de usar
cast(null as datatype) create table mytable as
select
field_a,
cast(null as varchar(1)) brand_new_field
from anothertable;
Mais informações aqui .
cast(null as datatype) create table mytable as
select
field_a,
cast(null as varchar(1)) brand_new_field
from anothertable;
