insert into z values (1);
insert into z values (1);
insert into z values (2);
insert into z values (3);
commit;
select c from z where (select z.c || '' from rdb$database) = '1';
C
==========
1
1
2
3
Description
create table z (c varchar(10));
insert into z values (1);
insert into z values (1);
insert into z values (2);
insert into z values (3);
commit;
select c from z where (select z.c || '' from rdb$database) = '1';
C
==========
1
1
2
3