added STEP4.1, STEP4.2, STEP5

skonev/greenplum/STEP4.2_dm.inactive_users_summary.sql

@@ -0,0 +1,28 @@
+/*
+ - 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
+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),
+	u.registration_date
+FROM core.dim_user u
+LEFT JOIN t1  USING (user_id)
+WHERE u.user_id NOT IN (SELECT user_id FROM core.fact_lesson_views)
+
+DISTRIBUTED BY (user_id);