SQL & PL/SQL

kindly have a look and guide what is wrong here? function compiled without error. my simple select statement is running fine

create or replace FUNCTION hr_get_attd_id
RETURN number 
IS
v_attd_id number:=0;
begin
 select nvl(max(attd_id),0)+1 into v_attd_id from STU_ATT_MST@EDULINKS_253;
 return v_attd_id;
end;

select * from hr_get_attd_id();

Error at line 1/15: ORA-22905: cannot access rows from a non-nested table item

please help.

with kind regards