What are the names and revenues of the companies with the highest revenues in each headquarter city?
return companies ;return headquarter cities of #1 ;return revenues of #1 ;return #1 where #3 is the  highest for each #2 ;return names of #4 ;return revenues  of #4 ;return #5 ,  #6
['select', 'project', 'project', 'group', 'project', 'project', 'union']