Convention Rules (CV)

CV03

Trailing comma policy in SELECT clauses.

Configure whether a trailing comma before FROM is forbidden (default) or required:

[rules.CV03]
select_clause_trailing_comma = "forbid"   # default
# select_clause_trailing_comma = "require"

forbid (default)

-- bad: trailing comma
select
    id,
    name,
from orders

-- good
select
    id,
    name
from orders

require

-- bad: missing trailing comma
select
    id,
    name
from orders

-- good
select
    id,
    name,
from orders

CV04

Consistent row-counting syntax: COUNT(*) vs COUNT(1).

Configure which form is required:

[rules.CV04]
prefer_count_1 = false   # default: require COUNT(*)
# prefer_count_1 = true  # require COUNT(1)

-- bad (with default config)
select count(1) from orders

-- good
select count(*) from orders

CV05

NULL comparisons must use IS NULL / IS NOT NULL.

Auto-fixable. Using = NULL or != NULL is never correct — SQL’s three-valued logic means those comparisons always return NULL, not TRUE or FALSE.

-- bad
select id from orders where deleted_at = null
select id from orders where status != null

-- good (auto-fixed)
select id from orders where deleted_at is null
select id from orders where status is not null

CV10

Identifiers must use a consistent quoting style within a file.

Mixing quoted and unquoted forms of the same identifier in a single file is flagged. Only the first inconsistency per identifier name is reported.

Handles double quotes ("col"), backticks (`col`), and brackets ([col]).

-- bad: 'col' used both unquoted and quoted
select col, "col" from t

-- bad: 'my_table' used both ways
select a
from my_table t
join "my_table" u on t.id = u.id

-- good: consistent throughout
select col from my_table

-- also good: consistently quoted
select "col" from "my_table"

Note: The comparison is case-insensitive. COL (unquoted) and "col" (quoted) are considered the same identifier for this rule.