Merge pull request 'feat(sql): complete window functions homework' (#105) from OS-418 into main

Reviewed-on: https://gitea.de-infra.servehttp.com/de-infrastructure/DWH/pulls/105 Reviewed-by: aleksey bogatyrev <abogatyrev@example.com>
2026-06-11 02:08:31 +04:00
parent 866db558a3 eb5cb22c96
commit a3eb1536b7
1 changed files with 152 additions and 0 deletions
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 /* Задание 1 */
 SELECT 
 	u.id,
 	u."name",
 	o.id AS order_id,
 	o.order_date,
 	ROW_NUMBER() OVER (
 		PARTITION BY u.id
 		ORDER BY o.order_date) AS order_number_for_user
 FROM 
 	users u 
 INNER JOIN
 	orders o ON u.id = o.user_id
 /* Задание 2 */
 WITH order_revenue_cte AS (
 	SELECT 
 		oi.order_id,
 		sum(oi.quantity * oi.price_at_purchase) AS order_revenue -- добавил агреграт по всем поз. в заказе
 	FROM 
 		order_items oi
 	GROUP BY oi.order_id 
 	)
 SELECT 
 	u.id AS user_id	,
 	u."name",
 	o.id AS order_id,
 	o.order_date,
 	orc.order_revenue,
 	sum(orc.order_revenue) OVER (
 		PARTITION BY u.id
 		ORDER BY o.order_date 
 	) AS running_revenue_for_user
 FROM 
 	users u 
 INNER JOIN
 	orders o ON u.id = o.user_id
 INNER JOIN 
 	order_revenue_cte orc ON o.id = orc.order_id
 WHERE o.status NOT IN ('cancelled', 'refunded') -- добавил условие не включать отмененные заказы
 /* Задание 3 */
 WITH user_revenue_cte AS (
 	SELECT 
 		o.user_id,
 		sum(oi.quantity * oi.price_at_purchase) AS user_total_revenue
 	FROM
 		orders o
 	INNER JOIN
 		order_items oi ON o.id = oi.order_id
 	GROUP BY o.user_id) -- добавил group by, костыль убран
 SELECT
 	u."name",
 	urc.user_total_revenue,
 	RANK() OVER (ORDER BY urc.user_total_revenue DESC) AS revenue_rank,
 	DENSE_RANK() OVER (ORDER BY urc.user_total_revenue DESC) AS revenue_dense_rank
 FROM 
 	users u 
 INNER JOIN 
 	user_revenue_cte urc ON u.id = urc.user_id;
 /* Задание 4 */
 SELECT 
 	u.name AS user_name,
 	o.id AS order_id,
 	o.order_date,
 	FIRST_VALUE(o.order_date) OVER (
 		PARTITION BY o.user_id
 		ORDER BY o.order_date
 	) AS first_order_date,
 	LAST_VALUE(o.order_date) OVER (
 		PARTITION BY o.user_id
 		ORDER BY o.order_date
 		ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
 	) AS last_order_date
 FROM 
 	users u 
 INNER JOIN
 	orders o ON u.id = o.user_id;
 /* Задание 5 */
 SELECT 
 	u.name,
 	o.id,
 	count(o.id) OVER (
 		PARTITION BY o.user_id) AS orders_per_user 
 FROM
 	users u 
 INNER JOIN 
 	orders o ON u.id = o.user_id 
 /* Задание 6 */
 WITH order_revenue_cte AS (
 	SELECT 
 		oi.order_id,
 		sum(oi.quantity * oi.price_at_purchase) AS order_revenue
 	FROM 
 		order_items oi
 	GROUP BY oi.order_id) -- добавил group by по order_id, теперь это сумма всего заказа, а не строки
 SELECT
 	u.name,
 	o.id,
 	o.order_date,
 	orc.order_revenue,
 	lag(orc.order_revenue) OVER (
 		PARTITION BY o.user_id
 		ORDER BY o.order_date
 	) AS prev_order_revenue
 FROM
 	users u 
 INNER JOIN
 	orders o ON u.id = o.user_id 
 INNER JOIN 
 	order_revenue_cte orc ON o.id = orc.order_id;
 /* Задание 7 */
 WITH category_revenue_cte AS (
 	SELECT
 		p.category, 
 		date_trunc('day', o.order_date)::date AS order_period,
 		sum(oi.quantity * oi.price_at_purchase) AS daily_category_revenue
 	FROM
 		products p 
 	LEFT JOIN
 		order_items oi ON p.id = oi.product_id 
 	INNER JOIN 
 		orders o ON oi.order_id = o.id
 	GROUP BY 1, 2)
 SELECT 
 	cr_cte.*,
 	sum(cr_cte.daily_category_revenue) OVER (
 		PARTITION BY cr_cte.category
 		ORDER BY cr_cte.order_period
 		ROWS UNBOUNDED PRECEDING
 	) AS running_category_revenue
 FROM 
 	category_revenue_cte cr_cte;