Bonifatsiy
89 lines
2.7 KiB
SQL
89 lines
2.7 KiB
SQL
-- Этап 3. Анализ и запросы - Напиши SQL-запросы к витринам -- Напиши свои вариации для практики--
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-- Топ-5 самых просматриваемых уроков
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SELECT
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lesson_title,
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course_title,
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total_views
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FROM lesson_popularity_summary
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ORDER BY total_views DESC
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LIMIT 5;
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-- Неактивные пользователи, записавшиеся на курсы
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SELECT
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name,
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email,
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registered_courses_count
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FROM inactive_users_summary
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WHERE registered_courses_count > 0
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ORDER BY registration_date DESC;
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-- Курсы с самым высоким процентом завершения
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SELECT
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course_title,
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AVG(completion_rate) AS avg_completion
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FROM course_completion_rate
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GROUP BY course_title
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ORDER BY avg_completion DESC
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LIMIT 5;
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-- Мои вариации --
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-- Среднее количество учеников на урок по каждому курсу
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SELECT
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course_title,
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ROUND(AVG(unique_users), 2) AS avg_users_lesson,
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SUM(total_views) AS total_course_views
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FROM dsolovianov.lesson_popularity_summary
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GROUP BY course_title
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ORDER BY avg_users_lesson DESC;
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-- Возрастное распределение неактивных пользователей
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SELECT
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CASE
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WHEN age < 25 THEN 'до 25'
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WHEN age BETWEEN 25 AND 30 THEN '25-30'
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WHEN age BETWEEN 31 AND 35 THEN '31-35'
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ELSE '35+'
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END AS age_group,
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COUNT(*) AS inactive_users_count,
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AVG(registered_courses_count) AS avg_courses_enrolled
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FROM dsolovianov.inactive_users_summary
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GROUP BY age_group
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ORDER BY age_group;
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-- Пользователи, которые начали, но не закончили курс (completion_rate между 0 и 1)
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SELECT
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user_name,
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course_title,
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lessons_viewed,
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lessons_in_course,
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ROUND(completion_rate * 100, 0) AS no_completion,
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(lessons_in_course - lessons_viewed) AS remaining_lessons
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FROM dsolovianov.course_completion_rate
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WHERE completion_rate BETWEEN 0.01 AND 0.99
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ORDER BY completion_rate DESC, user_name;
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-- Прогресс каждого пользователя по курсам (с указанием статуса)
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SELECT
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user_name,
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course_title,
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lessons_viewed,
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lessons_in_course,
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ROUND(completion_rate * 100, 0) AS progress_percent,
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CASE
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WHEN completion_rate = 1.0 THEN 'Пройден'
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WHEN completion_rate = 0 THEN 'Не начат'
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WHEN completion_rate >= 0.5 THEN 'В процессе (>50%)'
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ELSE 'В процессе (<50%)'
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END AS status
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FROM dsolovianov.course_completion_rate
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ORDER BY user_name, completion_rate DESC;
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