ClickHouse/tests/queries/0_stateless/01592_window_functions.sql

set allow_experimental_window_functions = 1;

drop table if exists product_groups;
drop table if exists products;

CREATE TABLE product_groups (
	group_id Int64,
	group_name String
) Engine = Memory;


CREATE TABLE products (
	product_id Int64,
	product_name String,
	price DECIMAL(11, 2),
	group_id Int64
) Engine = Memory;

INSERT INTO product_groups  VALUES	(1, 'Smartphone'),(2, 'Laptop'),(3, 'Tablet');

INSERT INTO products (product_id,product_name, group_id,price) VALUES (1, 'Microsoft Lumia', 1, 200), (2, 'HTC One', 1, 400), (3, 'Nexus', 1, 500), (4, 'iPhone', 1, 900),(5, 'HP Elite', 2, 1200),(6, 'Lenovo Thinkpad', 2, 700),(7, 'Sony VAIO', 2, 700),(8, 'Dell Vostro', 2, 800),(9, 'iPad', 3, 700),(10, 'Kindle Fire', 3, 150),(11, 'Samsung Galaxy Tab', 3, 200);

select '---- Q1 ----';

SELECT
	product_name,
	price,
	group_name,
	AVG(price) OVER (PARTITION BY group_name)
FROM products INNER JOIN  product_groups USING (group_id)
order by group_name, product_name, price;

select '---- Q2 ----';

SELECT
	product_name,
	group_name,
  price,
	rank() OVER (PARTITION BY group_name ORDER BY price) rank
FROM products INNER JOIN product_groups USING (group_id)
order by  group_name, rank, price;

select '---- Q3 ----';
SELECT
	product_name,
	group_name,
	price,
	row_number() OVER (PARTITION BY group_name ORDER BY price desc) rn
FROM products INNER JOIN product_groups USING (group_id)
ORDER BY group_name, rn;

select '---- Q4 ----';
SELECT *
FROM
(
    SELECT
        product_name,
        group_name,
        price,
        min(price) OVER (PARTITION BY group_name) AS min_price,
        dense_rank() OVER (PARTITION BY group_name ORDER BY price ASC) AS r
    FROM products
    INNER JOIN product_groups USING (group_id)
) AS t
WHERE min_price > 160
ORDER BY
    group_name ASC,
    r ASC,
    product_name ASC;

select '---- Q5 ----';
SELECT
	product_name,
	group_name,
	price,
	FIRST_VALUE (price) OVER (PARTITION BY group_name ORDER BY product_name desc) AS price_per_group_per_alphab
FROM products INNER JOIN product_groups USING (group_id)
order by group_name, product_name desc;

select '---- Q6 ----';
SELECT
	product_name,
	group_name,
	price,
	LAST_VALUE (price) OVER (PARTITION BY group_name ORDER BY
			price RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING
  ) AS highest_price_per_group
FROM
	products
INNER JOIN product_groups USING (group_id)
order by group_name, product_name;

select '---- Q7 ----';
select product_name, price, group_name, round(avg0), round(avg1)
from (
SELECT
	product_name,
	price,
	group_name,
	avg(price) OVER (PARTITION BY group_name ORDER BY price) avg0,
	avg(price) OVER (PARTITION BY group_name ORDER BY
			price RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) avg1
FROM products INNER JOIN  product_groups USING (group_id)) t
order by group_name, product_name, price;

drop table product_groups;
drop table products;