homework, pet project DE Dmitry_Medvedev #1

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dmitry_medvedev wants to merge 264 commits from md_branch into main
Showing only changes of commit 46a366c07a - Show all commits
@@ -4,7 +4,7 @@
DROP TABLE IF EXISTS dsolovianov.products ON CLUSTER clickhouse_cluster SYNC;
DROP TABLE IF EXISTS dsolovianov.prices ON CLUSTER clickhouse_cluster SYNC;
CREATE TABLE products
CREATE TABLE dsolovianov.products
ON CLUSTER clickhouse_cluster
(
product_id UInt32,
@@ -16,12 +16,12 @@ ON CLUSTER clickhouse_cluster
ORDER BY product_id;
INSERT INTO products VALUES
INSERT INTO dsolovianov.products VALUES
(101, 'iPhone 14'),
(102, 'Galaxy S22'),
(103, 'Pixel 7');
CREATE TABLE prices
CREATE TABLE dsolovianov.prices
ON CLUSTER clickhouse_cluster
(
product_id UInt32,
@@ -33,7 +33,7 @@ ON CLUSTER clickhouse_cluster
)
ORDER BY product_id;
INSERT INTO prices VALUES
INSERT INTO dsolovianov.prices VALUES
(101, 999, 'US'),
(101, 1049, 'EU'),
(102, 850, 'US'),
@@ -48,8 +48,8 @@ SELECT
p.name,
pr.price,
pr.region
FROM products AS p
ANY LEFT JOIN prices AS pr ON p.product_id = pr.product_id;
FROM dsolovianov.products AS p
ANY LEFT JOIN dsolovianov.prices AS pr ON p.product_id = pr.product_id;
--№2 Что будет, если в таблице `prices` несколько цен на один `product_id`?
@@ -62,8 +62,8 @@ SELECT
p.name,
pr.price,
pr.region
FROM products AS p
ALL LEFT JOIN prices AS pr ON p.product_id = pr.product_id;
FROM dsolovianov.products AS p
ALL LEFT JOIN dsolovianov.prices AS pr ON p.product_id = pr.product_id;
/* `ALL LEFT JOIN` в Clickhouse ведет себя также, как LEFT JOIN в SQL, то есть собирает все совпадения.
Начинается перегон данных между таблицами. Из-за этого растет нагрузка на ОЗУ и CPU.