Display Null Value In Data Grid Viewer Using C#

I have table in sql server for Employee, it has(id, Employee, director),so the director field is id of the director's name,  so the director is employee and has director also, only the first director hasn't director( one Employee has not director);now, i want to use datagridviewer in c# for display as this table (id, employee, director), so the first record will be the (id, employee, '  ');i use this query:"select emp.ID ,emp.Name ,dir.Name as'director'  from table1 emp, table1 dir where (emp.director=dir.ID OR  dir.director IS NULL)"but when i display the datagridviewer , it don't display the first employee(first director) which hasn't director.