diff --git a/gmokrousov/postgresql/DM_course_summary.sql b/gmokrousov/postgresql/DM_course_summary.sql new file mode 100644 index 0000000..e303798 --- /dev/null +++ b/gmokrousov/postgresql/DM_course_summary.sql @@ -0,0 +1,24 @@ +CREATE MATERIALIZED VIEW course_summary as + with + lw as ( + select + user_id, + lesson_id, + viewed_at + from lesson_views + ) + select + id as course_id, + title as course_title, + count(distinct e.user_id) as unique_users, + count(distinct l.lesson_id) as lessons_count, + count(distinct lw.viewed_at) as total_views, + round(count(distinct lw.viewed_at)::decimal / count(distinct e.user_id), 2) as avg_views_per_user, + min(lw.viewed_at) as first_viewed_at, + max(lw.viewed_at) as last_viewed_at + from + courses as c + join (select course_id, user_id from enrollments) as e on c.id = e.course_id + join (select id as lesson_id, course_id from lessons) as l on c.id = l.course_id + join lw on l.lesson_id = lw.lesson_id + group by id; \ No newline at end of file