Практика 'Типы данных' - ClickHouse

2026-05-14 13:13:47 +03:00
parent 318c50b563
commit fb29b369f6
3 changed files with 117 additions and 6 deletions
@@ -0,0 +1,111 @@
+-- Задание 1
+
+CREATE TABLE mnoskov.raw_data1
+ON CLUSTER clickhouse_cluster (
+  user_id String,
+  balance String,
+  created_at String
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/mnoskov/raw_data1',
+    '{replica}'
+)
+ORDER BY tuple();
+
+SELECT
+	user_id,
+	toDecimal64OrNull(balance,2) AS balance,
+	toDateTime64OrNull(created_at, 3) AS created_at
+FROM
+	mnoskov.raw_data1
+WHERE
+	balance IS NOT NULL AND created_at IS NOT NULL;
+
+
+-- Задание 2
+
+CREATE TABLE events 
+ON CLUSTER clickhouse_cluster (
+  event_id String,
+  event_date String,  -- форматы: "2023-01-01", "01.02.2023", "invalid"
+  event_time String   -- форматы: "12:30:45", "25:99:99"
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/mnoskov/events',
+    '{replica}'
+)
+ORDER BY
+	event_id;
+
+SELECT * FROM mnoskov.events;
+
+
+SELECT
+	event_id,
+	toDate(parseDateTimeBestEffortOrNull(event_date)) AS event_dates,
+	CASE
+		WHEN toDayOfMonth(parseDateTimeBestEffortOrNull(event_time)) = 1 THEN toHour(parseDateTimeBestEffortOrNull(event_time))
+		ELSE (toDayOfMonth(parseDateTimeBestEffortOrNull(event_time)) - 1) * 24 + toHour(parseDateTimeBestEffortOrNull(event_time))
+	END AS event_times,
+	toDateTime(parseDateTimeBestEffortOrNull(event_date)) + toIntervalHour(event_times) AS event_datetime
+FROM
+	mnoskov.events
+ORDER BY
+	event_dates;
+-- Все преобразования с to... и parse... нашел тут https://clickhouse.com/docs/ru/sql-reference/functions/type-conversion-functions#toIntervalMonth.
+-- explain analyze не работает, потэому не могу посмотреть насколько это эффективно, НО главное сам запрос работает.
+
+
+-- Задание 3
+
+CREATE TABLE mnoskov.user_activity
+ON CLUSTER clickhouse_cluster
+(
+  user_id UInt32,
+  actions String  -- JSON: ["login", "purchase", "logout"]
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/mnoskov/user_activity',
+    '{replica}'
+)
+ORDER BY
+	user_id;
+
+SELECT
+	user_id,
+	count(*)
+FROM
+	mnoskov.user_activity
+WHERE
+	has(JSONExtract(actions, 'Array(String)'), 'purchase')
+GROUP BY
+	user_id
+ORDER BY
+	user_id;
+
+
+-- Задание 4
+
+CREATE TABLE mnoskov.sensor_data
+ON CLUSTER clickhouse_cluster
+(
+  sensor_id UInt32,
+  value Float64,
+  status Enum('ok' = 1, 'error' = 2)
+)
+ENGINE = ReplicatedMergeTree(
+    '/clickhouse/tables/{shard}/mnoskov/sensor_data',
+    '{replica}'
+)
+ORDER BY sensor_id;
+
+--1-2.
+SELECT
+	toString(status) AS str_status,
+	avg(value) AS avg_value
+FROM
+	mnoskov.sensor_data
+GROUP BY
+	str_status;
+--3
+-- не понял задание. все строки в value можно преобразовать в Decimal(10,2), потому что value - Float64, а он все null переделывает в 0.