use ABDUczelnia

select distinct nazwisko, imie, Nip
from Wykladowcy as s join oceny as o on o.IdWykladowcy = o.IdStudenta
where o.ocena=2  and year(o.DataOceny)=2013 and month(o.dataoceny)<7
group by imie, nazwisko, Nip
having  count(o.ocena)>=2