CREATE VIEW V_3 AS select id_stud, stud_sname from student where stip=900 WITH CHECK OPTION

CREATE VIEW PR1 AS select id_stud, stud_sname from student where stip<>NULL

CREATE VIEW numb_3(N, NN) AS select subj_nam, count(id_subj) from progress group by id_subj

CREATE VIEW avg_mark AS select * from progress first where mark > (select avg(mark) from progress second where second.id_subj= first.id_subj)

CREATE VIEW P3 (nam, snam, n_stip) AS select stud_snam, stud_nam, stip*2 from student WHERE stip=1300