oracle 中,查找 小于指定日期的最近日期

create or replace function fn_GetNearDateFromTable(p_date int)
  return date is
  Result  date;
begin
  select max(a.datefiled)  into result  from tables a  where a.datefiled <= to_date(p_date, 'YYYYMMDD');
  Return result;
end fn_GetNearDateFromTable;