CREATE MATERIALIZED VIEW platform_summary AS

WITH stats AS (
	SELECT 
		(SELECT COUNT(*) total_users FROM pet_users pu) AS total_users,
		(SELECT COUNT(*) total_courses FROM pet_courses pc) AS total_courses,
		(SELECT COUNT(*) total_lessons FROM pet_lessons pl) AS total_lessons,
		(SELECT COUNT(DISTINCT user_id) FROM pet_lesson_views plv) AS users_with_views,
		(SELECT COUNT(*) FROM pet_lesson_views plv) AS total_views
)

SELECT
	total_users,
	total_courses,
	total_lessons, 
	users_with_views,
	
	ROUND((total_lessons * 1.0 / total_courses), 2) AS avg_lessons_per_course,
	ROUND((total_views * 1.0 / total_lessons), 2) AS avg_views_per_lesson
FROM stats;