Show the names of editors that are on at least two journal committees.
return editors ;return journal committees of #1 ;return the  number of  #2 ;return #1 where #3 is two ;return #1 where #3 is higher than two ;return #4 ,  #5 ;return the  names of #6
['select', 'project', 'aggregate', 'comparative', 'comparative', 'union', 'project']