delete from costage_st_hochschulsemester
where st_sem_nr in (select distinct st_sem_nr
from costage_st_hochschulsemester_neu);

insert into costage_st_hochschulsemester(st_studstamm_nr,
       st_sem_nr,
       anzahl_hochschulsemester)
select st_studstamm_nr,
       st_sem_nr,
       anzahl_hochschulsemester
from costage_st_hochschulsemester_neu;