hive sql

1. How to transform data into a map using group by in Hive SQL?

select 
  grade, 
  str_to_map(course_list,',',':') lecture_count_map
from (
  select 
    grade, 
    concat_ws(',',
      collect_list(concat_ws(':', lecture, cast(count as string)))
    ) course_list
  from courses
  group by grade
) T;

示意例子：