OS-314 fixes because I've broken full git struct

mdrozdov/greenplum/dm_layer.sql

@@ -0,0 +1,71 @@
+--lesson_popularity_summary data mart
+	create materialized view dm.lesson_popularity_summary as
+	select 
+		dl.lesson_id,
+		dl.title as lesson_title,
+		dl.course_id,
+		dc.title as course_title,
+		count(flv.lesson_id) as total_views,
+		count(distinct flv.user_id) as unique_users,
+		min(flv.viewed_at) as first_view,
+		max(flv.viewed_at) as last_view
+	from core.dim_lesson dl
+	left join core.dim_course dc 
+	    on dl.course_id = dc.course_id
+	left join core.fact_lesson_views flv 
+	    on dl.lesson_id = flv.lesson_id
+	group by dl.lesson_id, dl.title, dl.course_id, dc.title
+	
+	-- inactive_users_summary data mart
+	create materialized view dm.inactive_users_summary as
+	select
+		du.user_id,
+		du.name as user_name,
+		du.email,
+		du.age,
+		count(e.course_id) as enrollments_count,
+		du.registration_date
+	from core.dim_user du
+	left join core.enrollments e 
+		on du.user_id = e.user_id
+	left join core.fact_lesson_views flv 
+		on du.user_id = flv.user_id
+	where flv.user_id is null
+	group by du.user_id, du.name, du.email, du.age, du.registration_date
+	
+	-- course_completion_rate data mart
+	create materialized view dm.course_completion_rate as
+	with total_lessons_per_course as(
+		select
+			course_id,
+			count(*) as lessons_in_course
+		from core.dim_lesson
+		group by course_id
+	), lessons_viewed as (
+		select 
+			user_id,
+			course_id,
+			count(*) as lessons_viewed
+		from fact_lesson_views flv
+		group by user_id, course_id
+	)
+	select 
+		du.user_id as user_id,
+		du.name as user_name,
+		dc.course_id as course_id,
+		dc.title as course_title,
+		tlpc.lessons_in_course,
+		coalesce(lv.lessons_viewed, 0) as lessons_viewed,
+		round(
+			coalesce(
+				coalesce(lv.lessons_viewed, 0)*1.0/nullif(tlpc.lessons_in_course, 0), 0
+				), 2) as completion_rate
+	from core.enrollments e
+	join core.dim_user du 
+		on e.user_id = du.user_id
+	join total_lessons_per_course tlpc
+		on tlpc.course_id = e.course_id
+	join core.dim_course dc
+		on e.course_id = dc.course_id
+	left join lessons_viewed lv
+		on du.user_id = lv.user_id and dc.course_id = lv.course_id