dialect-clickhouse

name	dialect-clickhouse
description	Load when writing or debugging ClickHouse SQL, including backtick identifiers, ClickHouse casts, date bucket functions, string matching, aggregate functions, and engine-specific limitations.
entities	["clickhouse","sql","toStartOfMonth","formatDateTime","countIf","sumIf"]

ClickHouse SQL dialect

Use this skill for ClickHouse connections.

Syntax quick reference

Feature	ClickHouse syntax	Notes
Identifiers	`column`	Backticks are safest for reserved or mixed-case names.
Type casts	toUInt32(x), toString(x), CAST(x, 'Type')	Prefer typed conversion functions when clear.
String concat	concat(a, b)	Not PostgreSQL `
Pattern match	LIKE, match(value, 'regex')	match uses RE2-style regex.
Date bucket	toStartOfHour(ts), toStartOfDay(ts), toStartOfMonth(ts)	Use these instead of date_trunc.
Date format	formatDateTime(ts, '%Y-%m')	Similar strftime-style tokens.
Conditional aggregate	countIf(condition), sumIf(value, condition)	Prefer native combinators for concise analytics.

Some older ClickHouse versions have limited window function support. If a window query fails, rewrite with grouped subqueries or array functions.

Example

SELECT
  toStartOfMonth(created_at) AS month,
  status,
  count() AS order_count,
  sum(total_amount) AS revenue
FROM `orders`
WHERE created_at >= now() - INTERVAL 6 MONTH
GROUP BY month, status
ORDER BY month, status
LIMIT 500;