INSERT INTO studenci (id, Imie, Nazwisko, Pesel)
VALUES 
(1, 'Jan', 'Kowalski', '90090512345'),
(2, 'Anna', 'Nowak', '93071012345'),
(3, 'Piotr', 'Zieliński', '92021512345');

select * from studenci;
select * from studenci2;



create procedure [dbo].[wstaw_wiek] as
begin 
declare @student_id int, @Imie varchar(20) not null, @Nazwisko varchar(25) not null, @Pesel varchar(11) not null, @Wiek int not null;
declare StudentCursor cursor for 
select id,Imie,Nazwisko,Pesel from studenci;

open StudentCursor;

fetch next from StudentCursor into @student_id, @Imie,@Nazwisko,@Pesel;

while @@FETCH_STATUS = 0
begin 
set @Wiek = datediff(year,substring(@Pesel,1,6)getdate());
insert into studenci2(id_studenta,wiek) values(@student_id,@wiek);

fetch next from StudentCursor into @student_id,@Imie,@Nazwisko,@Pesel;
end;

close StudentCursor;
deallocate StudentCursor;
end; 



execute wstaw_wiek;