diff --git a/mnoskov/postgresql/Пет-проект: Онлайн-курсы/2. Создание отчетности (витрин)/DQL_materialized_view_courses_popularity.sql b/mnoskov/postgresql/Пет-проект: Онлайн-курсы/2. Создание отчетности (витрин)/DQL_materialized_view_courses_popularity.sql new file mode 100644 index 0000000..3377eb5 --- /dev/null +++ b/mnoskov/postgresql/Пет-проект: Онлайн-курсы/2. Создание отчетности (витрин)/DQL_materialized_view_courses_popularity.sql @@ -0,0 +1,39 @@ +CREATE MATERIALIZED VIEW lesson_popularity_ranking as +WITH lesson_views_results AS ( + SELECT + lv.lesson_id, + count(lv.user_id) AS total_views, + count(DISTINCT lv.user_id) AS unique_viewers + FROM + lesson_views lv + GROUP BY + lv.lesson_id +), +enrollments_results AS ( + SELECT + e.course_id, + count(e.user_id) AS enrolled_to_course + FROM + enrollments e + GROUP BY + e.course_id +) +SELECT + l.id AS lesson_id, + l.title AS lesson_title, + c.title AS course_title, + lvr.total_views, + lvr.unique_viewers, + round(lvr.total_views / lvr.unique_viewers::numeric, 2) AS avg_views_per_viewer, + dense_rank() OVER (ORDER BY lvr.total_views desc) AS popularity_rank, + round((lvr.unique_viewers / er.enrolled_to_course::numeric) * 100, 0) || '%' AS completion_rate +FROM + lessons l +JOIN + courses c ON l.course_id = c.id +JOIN + lesson_views_results lvr ON l.id = lvr.lesson_id +JOIN + enrollments_results er ON c.id = er.course_id +ORDER BY + popularity_rank; \ No newline at end of file