How many people whose age is greater 30 and job is engineer?
return people ;return ages of  #1 ;return #1 where  #2 is  higher than 30 ;return jobs of  #1 ;return #1 where  #4 is  engineer ;return #1 of  both #3 and #5 ;return number of #6
['select', 'project', 'comparative', 'project', 'comparative', 'intersection', 'aggregate']