DROP MATERIALIZED VIEW IF EXISTS dm.lesson_popularity_summary;
CREATE MATERIALIZED VIEW dm.lesson_popularity_summary
DISTRIBUTED BY (lesson_id)
AS
select
	t1.lesson_id as lesson_id,
	dl.title as lesson_title,
	t1.course_id as course_id,
	dc.title as course_title,
	t1.total_views as total_views,
	t1.unique_users as unique_users,
	t1.first_view as first_view,
	t1.last_view as last_view
from
	(select 
		flv.lesson_id,
		flv.course_id,
		COUNT(*) as total_views,
		COUNT(distinct flv.user_id) as unique_users,
		MIN(flv.viewed_at) as first_view,
		MAX(flv.viewed_at) as last_view
	from 
		core.fact_lesson_views flv
	group by
		flv.lesson_id,
		flv.course_id
		) as t1
right join core.dim_lesson dl on dl.lesson_id = t1.lesson_id
left join core.dim_course dc on t1.course_id = dc.course_id;