Код: Выделить всё
create table tst1 (
f1 char(6) not null primary key,
f2 char(6)
);
insert into tst1 values('f1', 'f2')
select rdb$description from rdb$database;
RDB$DESCRIPTION
=================
<null>
select count(*) from rdb$database where rdb$description not in (select f1 from tst1);
COUNT
===========
1
select count(*) from rdb$database where rdb$description not in (select f2 from tst1);
COUNT
===========
0
select count(*) from rdb$database where rdb$description not in ('1', '2');
COUNT
===========
0