SERGEY_KONEV
48 lines
1019 B
PL/PgSQL
48 lines
1019 B
PL/PgSQL
BEGIN;
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CREATE MATERIALIZED VIEW course_summary AS
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WITH courses_users AS (
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SELECT
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c.id AS course_id,
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c.title AS course_name,
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COUNT(DISTINCT user_id) AS unique_users
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FROM courses c
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LEFT join enrollments e ON c.id = e.course_id
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GROUP BY c.id, c.title
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),
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courses_views AS (
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SELECT
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l.course_id,
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COUNT(lv.id) AS total_views,
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MAX(lv.viewed_at) AS last_viewed_at,
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MIN(lv.viewed_at) AS first_viewed_at
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FROM lessons l
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JOIN lesson_views lv ON l.id = lv.lesson_id
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GROUP BY l.course_id
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),
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courses_lessons AS (
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SELECT
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course_id,
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COUNT(DISTINCT id) AS lessons_count
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FROM lessons
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GROUP BY course_id
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)
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SELECT
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cu.course_id,
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cu.course_name,
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cu.unique_users,
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cl.lessons_count,
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cv.total_views,
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ROUND(cv.total_views::DECIMAL / NULLIF(cu.unique_users, 0), 2) AS avg_views_per_user,
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cv.first_viewed_at,
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cv.last_viewed_at
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FROM courses_users cu
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LEFT JOIN courses_views cv USING(course_id)
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LEFT JOIN courses_lessons cl USING(course_id)
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ORDER BY cu.course_id;
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COMMIT;
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