From e8ad05df8bf0d621331cd7df614ff27f7784a9ec Mon Sep 17 00:00:00 2001
From: Dmitry Medvedev <dmitri.medv15@gmail.com>
Date: Thu, 18 Jun 2026 15:04:51 +0500
Subject: [PATCH] added Mat VIEW Activity users for pet project

---
 dmedvedev/11.1 Pet project Activity users.sql | 63 +++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 dmedvedev/11.1 Pet project Activity users.sql

diff --git a/dmedvedev/11.1 Pet project Activity users.sql b/dmedvedev/11.1 Pet project Activity users.sql
new file mode 100644
index 0000000..150c80d
--- /dev/null
+++ b/dmedvedev/11.1 Pet project Activity users.sql	
@@ -0,0 +1,63 @@
+--Активность пользователей
+
+CREATE MATERIALIZED VIEW user_activity_summary AS
+
+--CTE кол-во курсов на которые записан пользователь
+WITH enrollment_count AS (
+	SELECT 
+		pe.user_id,
+		COUNT(*) AS enrollment_count
+	FROM pet_enrollments pe 
+	GROUP BY pe.user_id
+),
+--CTE просмотренные уникальные уроки пользователем (кол-во)
+viewed_lessons_count AS (
+	SELECT 
+		plv.user_id,
+		DENSE_RANK() OVER(
+			PARTITION BY plv.user_id
+			ORDER BY plv.lesson_id
+		) AS viewed_lessons_count
+	FROM  pet_lesson_views plv 
+),
+
+--CTE дата и время последнего просмотра урока
+last_view AS (
+	SELECT 
+		plv.user_id,
+		LAST_VALUE(plv.viewed_at) OVER (
+			PARTITION BY plv.user_id
+			ORDER BY plv.viewed_at
+			ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING 
+		) AS last_view
+	FROM pet_lesson_views plv
+),
+
+--CTE дата и время первого просмотра урока
+first_view AS (
+	SELECT 
+		plv.user_id,
+		FIRST_VALUE(plv.viewed_at) OVER (
+			PARTITION BY plv.user_id
+			ORDER BY plv.viewed_at 
+		) AS first_view
+	FROM pet_lesson_views plv
+)
+
+SELECT 
+	pu.id AS user_id, 
+	pu.name AS name,
+	ec.enrollment_count AS enrollment_count,
+	MAX(vlc.viewed_lessons_count) AS viewed_lessons_count,
+	last_view,
+	first_view,
+	ROUND(MAX(vlc.viewed_lessons_count * 100.0 / (SELECT COUNT(*) FROM pet_lessons pl)), 2) || '%' AS engagement_rate
+	
+FROM pet_users pu 
+LEFT JOIN enrollment_count ec ON pu.id = ec.user_id
+LEFT JOIN viewed_lessons_count vlc ON pu.id = vlc.user_id 
+LEFT JOIN last_view lv ON pu.id = lv.user_id
+LEFT JOIN first_view fv ON pu.id = fv.user_id
+
+GROUP BY pu.id, ec.enrollment_count, last_view, first_view
+ORDER BY pu.id;
\ No newline at end of file