are there any nonstop flights leaving from dallas to baltimore july seventh with who united airlines 
return flights ;return #1 on united airlines ;return #2 that are leaving from  dallas ;return #3 to baltimore ;return #4 on july seventh ;return #5 that are nonstop ;return number of  #6 ;return if #7 is at least one
['select', 'filter', 'filter', 'filter', 'filter', 'filter', 'aggregate', 'boolean']