Исправил недочёты после код-ревью.

1 - Пет-проект_Онлайн-курсы/2.1 DDL_CREATE_MAT_VIEW_user_activity_summary.sql

@@ -20,9 +20,7 @@ inner join edu_platform.lesson_views lv on u.id = lv.user_id
 left join edu_platform.lessons l on lv.lesson_id  = l.id
 left join edu_platform.lessons l2 on e.course_id  = l2.course_id
 group by 
-	u.id, u.name
-ORDER by
-	u.id;
+	u.id, u.name;
 
 -- После анализа EXPLAIN
 -- Убрал диблирование строк, возникающее при Join-ах.
@@ -41,7 +39,7 @@ users_enroll as (
 	select
 		u.id as user_id ,
 		u.name as name,
-		COUNT(e.course_id) as enrollment_count,
+		COUNT(DISTINCT e.course_id) as enrollment_count,
 		SUM(cl.lesson_count) as lesson_sum
 	from
 		edu_platform.users u
@@ -57,7 +55,6 @@ users_lesson_views as (
 		MIN(lv.viewed_at) as first_view
 	from
 		edu_platform.lesson_views lv
-	left join edu_platform.lessons l on lv.lesson_id  = l.id
 	group by lv.user_id
 )
 select 
@@ -67,12 +64,10 @@ select
 	ulv.viewed_lessons_count,
 	ulv.last_view,
 	ulv.first_view,
-	ROUND( (ulv.viewed_lessons_count * 100.0) / nullif(lesson_sum, 0),
+	ROUND( (nullif(ulv.viewed_lessons_count, 0) * 100.0) / ue.lesson_sum,
 	2) as engagement_rate
 from users_enroll ue
-inner join users_lesson_views ulv on ue.user_id = ulv.user_id
-order by
-	user_id;
+left join users_lesson_views ulv on ue.user_id = ulv.user_id;
 
 
 

1 - Пет-проект_Онлайн-курсы/2.2 DDL_CREATE_MAT_VIEW_course_summary.sql

@@ -48,5 +48,4 @@ from
 	edu_platform.courses c
 LEFT JOIN enroll e ON c.id = e.course_id
 LEFT JOIN lessons l ON c.id = l.course_id
-LEFT JOIN views v ON c.id = v.course_id
-ORDER BY c.id;
+LEFT JOIN views v ON c.id = v.course_id;