ID   name Surname
1    Mark Anthony
2    Julius Ceasar
3    Marcus Crassus

ID   name   Surname
1    Marcus Caelius
2    Julius Ceasar
3    Sevilius Casca
4    Marcus Crassus

ID   name   Surname
1    Marcus Caelius
2    Julius Ceasar
3    Sevilius Casca
4    Marcus Crassus
5    Mark Anthony

insert into b(name, surname)
    select name, surname
    from a
    where not exists (select 1 from b where b.name = a.name and b.surname = a.surname);