create table tab(id int, val int);
create table tab1(id int, val int);
create table tab2(id int, val int);
create table tab3(id int, val int);
//
create trigger TR_tab_AI after insert on tab
for each row
begin
  case new.id
    when 1 then insert tab1(id,val) values(new.id, new.val);
    when 2 then insert tab2(id,val) values(new.id, new.val);
    else insert tab3(id,val) values(new.id, new.val);
  end case;
end;
//
insert tab values(1,11),(2,21),(1,12);
insert tab values(5,51),(6,61),(1,13),(5,52);
//
select * from tab;
select * from tab1;
select * from tab2;
select * from tab3;