set serveroutput on
declear
v_name %type;
v_sal %type;
v_a integer;
v_b integer;
begin
v_a:=&150;
v_b:=&550;
select * from employees
where employee_id=v_a or employee_id=v_b;
DBMS_output.put_line(v_name|' '|v_sal);
exception
when no_data_found then
dbms_output.put_line('there is no such an employee!');
when too_many_rows then
for v_emp in (select * from employees where employee_id=v_a or employee_id=v_b)loop
DBMS_output.put_line(v_name|' '|v_sal);
end loop;
end;