create materialized view platform_summary as 
	with 
        lv_stats as (
            select 
                count(distinct user_id) as users_with_views,
                count(*)::decimal / nullif(count(distinct lesson_id), as avg_views_per_lesson
            from lesson_views
    	)
	select 
		total_users,
		total_courses,
		total_lessons,
		users_with_views,
		round((total_lessons::decimal / nullif(total_courses, 2)), 2) AS avg_lessons_per_course,
		round(avg_views_per_lesson, 2) as avg_views_per_lesson
	from 
		(
		select 
			(select count(*) from users) as total_users,
			(select count(*) from courses) as total_courses,
			count(*) as total_lessons
		from lessons
	) as s
	cross join lv_stats as lv;