For each grade, report the grade, the number of classrooms in which it is taught and the total number of students in the grade.
return grades ;return classrooms of  #1 ;return number of #2 for each #1 ;return students of  #1 ;return number of #4 for each #1 ;return #1 ,   #3 , #5
['select', 'project', 'group', 'project', 'group', 'union']