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ДЗ к уроку 10 #9

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103 changes: 103 additions & 0 deletions HomeWork_Lesson-10.sql
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-- Провести аналитику в разрезе групп.

-- Построить запрос, который будет выводить следующие столбцы:

-- имя группы
-- среднее количество пользователей в группах
-- самый молодой пользователь в группе
-- самый пожилой пользователь в группе
-- количество пользователей в группе
-- всего пользователей в системе
-- отношение в процентах (количество пользователей в группе / всего пользователей в системе) * 100

SELECT DISTINCT
communities.name AS group_name,
COUNT(communities_users.user_id) OVER()
/ (SELECT COUNT(*) FROM communities) AS avg_users_in_groups,
FIRST_VALUE(users.id)
OVER(PARTITION BY communities.id ORDER BY profiles.birthday DESC) AS youngest,
FIRST_VALUE(users.id)
OVER(PARTITION BY communities.id ORDER BY profiles.birthday) AS oldest,
COUNT(communities_users.user_id)
OVER(PARTITION BY communities.id) AS users_in_groups,
COUNT(users.id) OVER() AS users_total,
COUNT(communities_users.user_id) OVER(PARTITION BY communities.id)
/ COUNT(users.id) OVER() *100 AS '%%'
FROM communities
JOIN communities_users
ON communities_users.community_id = communities.id
JOIN users
ON communities_users.user_id = users.id
JOIN profiles
ON profiles.user_id = users.id;

SELECT DISTINCT
communities.name AS group_name,
COUNT(communities_users.user_id) OVER()
/ (SELECT COUNT(*) FROM communities) AS avg_users_in_groups,
FIRST_VALUE(users.first_name)
OVER(PARTITION BY communities.id ORDER BY profiles.birthday DESC) AS youngest_first_name,
FIRST_VALUE(users.last_name)
OVER(PARTITION BY communities.id ORDER BY profiles.birthday DESC) AS youngest_last_name,
FIRST_VALUE(users.first_name)
OVER(PARTITION BY communities.id ORDER BY profiles.birthday) AS oldest_first_name,
FIRST_VALUE(users.last_name)
OVER(PARTITION BY communities.id ORDER BY profiles.birthday) AS oldest_last_name,
COUNT(communities_users.user_id)
OVER(PARTITION BY communities.id) AS users_in_groups,
COUNT(users.id) OVER() AS users_total,
COUNT(communities_users.user_id) OVER(PARTITION BY communities.id)
/ COUNT(users.id) OVER() *100 AS '%%'
FROM communities
JOIN communities_users
ON communities_users.community_id = communities.id
JOIN users
ON communities_users.user_id = users.id
JOIN profiles
ON profiles.user_id = users.id;

SELECT DISTINCT
communities.name AS group_name,
COUNT(communities_users.user_id) OVER()
/ (SELECT COUNT(*) FROM communities) AS avg_users_in_groups,
FIRST_VALUE(users.first_name)
OVER birthday_desc AS youngest_first_name,
FIRST_VALUE(users.last_name)
OVER birthday_desc AS youngest_last_name,
FIRST_VALUE(users.first_name)
OVER birthday_asc AS oldest_first_name,
FIRST_VALUE(users.last_name)
OVER birthday_asc AS oldest_last_name,
COUNT(communities_users.user_id)
OVER(PARTITION BY communities.id) AS users_in_groups,
COUNT(users.id) OVER() AS users_total,
COUNT(communities_users.user_id) OVER(PARTITION BY communities.id)
/ COUNT(users.id) OVER() *100 AS '%%'
FROM communities
JOIN communities_users
ON communities_users.community_id = communities.id
JOIN users
ON communities_users.user_id = users.id
JOIN profiles
ON profiles.user_id = users.id
WINDOW birthday_desc AS (PARTITION BY communities.id ORDER BY profiles.birthday DESC),
birthday_asc AS (PARTITION BY communities.id ORDER BY profiles.birthday);


SELECT
ROW_NUMBER() OVER w AS 'row_number',
from_user_id,
created_at,
LEAD(created_at) OVER w AS 'LEAD',
LAG(created_at) OVER w AS 'LAG'
FROM messages
WINDOW w AS (PARTITION BY (from_user_id) ORDER BY created_at);

SELECT
ROW_NUMBER() OVER w AS 'row_number',
from_user_id,
created_at,
LAG(created_at) OVER w AS 'LAG',
TIMESTAMPDIFF(SECOND, LAG(created_at) OVER w, created_at) AS difference
FROM messages
WINDOW w AS (PARTITION BY (from_user_id) ORDER BY created_at);