Show all director names who have a movie in the year 1999 or 2000.
return directors ;return movies of  #1 ;return years of  #2 ;return #1 where #3 is  1999 ;return #1 where #3 is  2000 ;return #4 or  #5 ;return names of  #6
['select', 'project', 'project', 'comparative', 'comparative', 'union', 'project']