If exactly three white ducks are standing in a row on dry ground.
return ducks ;return #1 that are white ;return #2 standing in  a  row ;return dry ground ;return #3 that are on #4 ;return the  number of  #5 ;return if  #6 is equal to  three
['select', 'filter', 'filter', 'select', 'filter', 'aggregate', 'boolean']