PLS-00103: Encountered the symbol when expecting one of the following:

The keyword for Oracle PL/SQL is “ELSIF” ( no extra “E”), not ELSEIF (yes, confusing and stupid)

declare
    var_number number;
begin
    var_number := 10;
    if var_number > 100 then
       dbms_output.put_line(var_number||' is greater than 100');
    elsif var_number < 100 then
       dbms_output.put_line(var_number||' is less than 100');
    else
       dbms_output.put_line(var_number||' is equal to 100');
    end if;
end;