show me all flights direct and connecting from boston to pittsburgh that arrive in pittsburgh before 10am 
return flights ;return #1 from  boston ;return #2 that  arrive in pittsburgh  ;return #3 before 10am ;return #4 that  are connecting ;return #4 that  are direct ;return #5 , #6
['select', 'filter', 'filter', 'filter', 'filter', 'filter', 'union']