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ДЗ к уроку 8 #7

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ДЗ к уроку 8 #7

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38 changes: 38 additions & 0 deletions HomeWork-Lesson8.sql
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Original file line number Diff line number Diff line change
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-- Подсчитать общее количество лайков, которые получили 10 самых молодых пользователей

SELECT count(*)
FROM likes
JOIN target_types ON target_types.id = likes.target_type_id
JOIN (SELECT user_id FROM profiles ORDER BY birthday DESC limit 10) AS youngest
ON youngest.user_id = likes.target_id
WHERE target_types.name = 'users';

-- Определить кто больше поставил лайков (всего) - мужчины или женщины

SELECT profiles.gender,
COUNT(likes.id) AS total_likes
FROM likes
JOIN profiles
ON likes.user_id = profiles.user_id
GROUP BY profiles.gender
ORDER BY total_likes DESC
LIMIT 1;

-- Найти 10 пользователей, которые проявляют наименьшую активность в использовании социальной сети.

SELECT users.id,
COUNT(DISTINCT messages.id) +
COUNT(DISTINCT likes.id) +
COUNT(DISTINCT media.id) AS activity
FROM users
LEFT JOIN messages
ON users.id = messages.from_user_id
LEFT JOIN likes
ON users.id = likes.user_id
LEFT JOIN media
ON users.id = media.user_id
GROUP BY users.id
ORDER BY activity
LIMIT 10;