show me all flights both direct and connecting to either san francisco or oakland from boston that arrive before 2pm 
return flights ;return #1 from boston ;return #2 to  san francisco ;return #2 to  oakland ;return #3 that  arrive before 2pm ;return #4 that  arrive before 2pm ;return #5 ,  #6
['select', 'filter', 'filter', 'filter', 'filter', 'filter', 'union']