i would like the first flight from dallas into houston on march first and the last flight from houston back to dallas on march first 
return flights ;return #1 from dallas  ;return #2 to  houston  ;return #3 on march  first  ;return #4 that  is  the  first  ;return #1 from houston  ;return #6 to  dallas  ;return #7 on march  first  ;return #8 that  is  the  last ;return #5 ,  #9
['select', 'filter', 'filter', 'filter', 'filter', 'filter', 'filter', 'filter', 'filter', 'union']