How many bookings did each customer make? List the customer id, first name, and the count.
return customers ;return customer  ids of  #1 ;return first names of  #1 ;return bookings of  #1 ;return number of #4 for each #1 ;return #2 ,   #3 , #5
['select', 'project', 'project', 'project', 'group', 'union']