From c5381da2481e094f9ad1dd821d0b2c2d5e0f5bcd Mon Sep 17 00:00:00 2001
From: mnoskov <bather.plaint5x@icloud.com>
Date: Fri, 20 Mar 2026 12:56:57 +0300
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---
 .../DQL_materialized_view_reporting_on_interactions.sql | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 mnoskov/postgresql/Пет-проект: Онлайн-курсы/2. Создание отчетности (витрин)/DQL_materialized_view_reporting_on_interactions.sql

diff --git a/mnoskov/postgresql/Пет-проект: Онлайн-курсы/2. Создание отчетности (витрин)/DQL_materialized_view_reporting_on_interactions.sql b/mnoskov/postgresql/Пет-проект: Онлайн-курсы/2. Создание отчетности (витрин)/DQL_materialized_view_reporting_on_interactions.sql
new file mode 100644
index 0000000..32fbe79
--- /dev/null
+++ b/mnoskov/postgresql/Пет-проект: Онлайн-курсы/2. Создание отчетности (витрин)/DQL_materialized_view_reporting_on_interactions.sql	
@@ -0,0 +1,48 @@
+CREATE MATERIALIZED VIEW platform_summary as
+WITH users_count AS (
+	SELECT
+		count(*) AS total_users
+	FROM
+		users
+),
+courses_count AS (
+	SELECT
+		count(*) AS total_courses
+	FROM
+		courses
+),
+lessons_count AS (
+	SELECT
+		count(*) AS total_lessons
+	FROM
+		lessons
+),
+users_with_views AS (
+	SELECT
+		count(distinct user_id) AS users_with_views
+	FROM
+		lesson_views
+),
+views_count AS (
+	SELECT
+		count(*) AS total_views
+	FROM
+		lesson_views lv
+)
+SELECT
+	uc.total_users,
+	cc.total_courses,
+	lc.total_lessons,
+	uwv.users_with_views,
+	round(lc.total_lessons / cc.total_courses::NUMERIC, 2) AS avg_lessons_per_course,
+	round(vc.total_views / lc.total_lessons::NUMERIC, 2) AS avg_views_per_lesson
+FROM
+	users_count uc
+CROSS JOIN
+	courses_count cc
+CROSS JOIN
+	lessons_count lc
+CROSS JOIN
+	users_with_views uwv
+CROSS JOIN
+	views_count AS vc;
\ No newline at end of file