Capitalisation Rules (CP)

All capitalisation rules enforce lowercase. This matches the style used by sqlfmt and is the default for most dbt projects. All five rules are auto-fixable with --fix.

CP01

Keywords must be lowercase.

Covers: SELECT, FROM, WHERE, GROUP BY, ORDER BY, HAVING, LIMIT, JOIN, UNION, AND, OR, NOT, IN, IS, LIKE, BETWEEN, CASE, WHEN, THEN, ELSE, END, AS, DISTINCT, ALL, ON, WITH, and all other SQL keywords.

-- bad
SELECT id, name
FROM orders
WHERE status = 'active'

-- good
select id, name
from orders
where status = 'active'

CP02

Unquoted identifiers must be lowercase.

Applies to table names, column names, CTE names, and aliases that are written without quotes. Quoted identifiers (e.g. "MyTable") are exempt.

-- bad
select OrderId, CustomerName
from Orders o

-- good
select orderid, customername
from orders o

CP03

Function names must be lowercase.

Applies to any name token immediately followed by (.

-- bad
SELECT COUNT(id), COALESCE(name, 'unknown'), UPPER(email)
FROM customers

-- good
select count(id), coalesce(name, 'unknown'), upper(email)
from customers

CP04

Boolean and null literals must be lowercase.

Covers TRUE, FALSE, and NULL.

-- bad
select id
from orders
where is_active = TRUE and deleted_at IS NULL

-- good
select id
from orders
where is_active = true and deleted_at is null

CP05

Data type names must be lowercase.

Covers: int, integer, bigint, smallint, float, double, decimal, numeric, varchar, char, text, boolean, bool, date, time, timestamp, timestamptz, json, jsonb, uuid, and others.

-- bad (in a CAST expression)
select cast(id as VARCHAR(36)), cast(amount as DECIMAL(10, 2))
from orders

-- good
select cast(id as varchar(36)), cast(amount as decimal(10, 2))
from orders