/*
 - ВИТРИНА АНАЛИЗА НЕАКТИВНЫХ ПОЛЬЗОВАТЕЛЕЙ
 - ВСЕ УЧАСТВУЮЩИЕ ТАБЛИЦЫ DISTRIBUTED BY (user_id)
 - ИТОГОВОЕ ПРЕДСТВАЛЕНИЕ ТАК ЖЕ DISTRIBUTED BY (user_id)
 */


CREATE MATERIALIZED VIEW IF NOT EXISTS dm.inactive_users_summary AS
-- EXPLAIN ANALYZE
DISTRIBUTED BY (user_id)
WITH t1 AS (
SELECT 
	user_id,
	count(DISTINCT course_id) AS enrollments_count
FROM core.enrollments
GROUP BY user_id
)
SELECT
	u.user_id,
	u.name AS user_name,
	u.email,
	u.age,
	coalesce(t1.enrollments_count, 0) AS enrollments_count,
	u.registration_date
FROM core.dim_user u
LEFT JOIN t1  USING (user_id)
WHERE u.user_id NOT EXISTS (SELECT user_id FROM core.fact_lesson_views);