Lint Rules¶

Scythe includes 22 built-in rules and integrates sqruff for additional SQL style and formatting rules.

Scythe rules (22)¶

Safety¶

Code	Name	Description	Default
`SC-S01`	`update-without-where`	UPDATE without WHERE affects all rows	Error
`SC-S02`	`delete-without-where`	DELETE without WHERE affects all rows	Error
`SC-S03`	`no-select-star`	SELECT * makes queries fragile when columns change	Warn
`SC-S04`	`unused-params`	Declared parameter placeholders ($N) not all used	Warn
`SC-S05`	`missing-returning`	DML with :one/:many command should have a RETURNING clause	Warn
`SC-S06`	`ambiguous-column-in-join`	SELECT with JOIN has unqualified column references	Warn

Codegen¶

Code	Name	Description	Default
`SC-C01`	`missing-returns-annotation`	Query should have a @returns annotation (enforced by parser)	Off
`SC-C02`	`exec-with-returning`	:exec command but query has RETURNING clause -- returned rows will be discarded	Warn
`SC-C03`	`duplicate-query-names`	Multiple queries share the same @name	Error

Naming¶

Code	Name	Description	Default
`SC-N01`	`prefer-snake-case-columns`	Column aliases should use snake_case	Warn
`SC-N02`	`prefer-snake-case-tables`	Table names should use snake_case	Warn
`SC-N03`	`query-name-convention`	Query name should start with an action verb	Warn
`SC-N04`	`consistent-alias-casing`	Table aliases should be lowercase	Warn

Antipattern¶

Code	Name	Description	Default
`SC-A01`	`not-equal-null`	Comparing with NULL using = or != always yields NULL; use IS NULL / IS NOT NULL	Error
`SC-A02`	`implicit-type-coercion`	Implicit type coercion may cause unexpected behavior	Off
`SC-A03`	`or-in-join-condition`	OR in JOIN ON condition usually prevents index usage	Warn

Performance¶

Code	Name	Description	Default
`SC-P01`	`order-without-limit`	ORDER BY without LIMIT may cause unnecessary sorting of large result sets	Warn
`SC-P02`	`like-starts-with-wildcard`	LIKE pattern starting with % prevents index usage	Warn
`SC-P03`	`not-in-subquery`	NOT IN (SELECT ...) has unexpected NULL behavior; prefer NOT EXISTS	Warn

Style¶

Code	Name	Description	Default
`SC-T01`	`prefer-explicit-join`	Implicit join (FROM a, b WHERE ...) -- prefer explicit JOIN syntax	Warn
`SC-T02`	`prefer-coalesce-over-case`	CASE WHEN x IS NULL THEN y ELSE x END can be COALESCE(x, y)	Warn
`SC-T03`	`prefer-count-star`	COUNT(1) is equivalent to COUNT() -- prefer COUNT() for clarity	Warn

Configuration¶

Override severity per-rule or per-category in scythe.toml:

[lint.rules]
"SC-S03" = "error"      # Promote no-select-star to error
"SC-A02" = "warn"       # Enable implicit-type-coercion
"SC-T03" = "off"        # Disable prefer-count-star

[lint.categories]
safety = "error"         # All safety rules become errors
style = "off"            # Disable all style rules

Severity levels: error, warn, off.

Priority: per-rule override > per-category override > default severity.

Sqruff rules¶

Scythe integrates sqruff for SQL formatting and style linting. Sqruff violations are prefixed with SQ- followed by the sqruff rule code.

Category	Rules	Description
`AL`	AL01-AL07	Aliasing rules
`AM`	AM01-AM07	Ambiguity rules
`CP`	CP01-CP05	Capitalization rules
`CV`	CV01-CV11	Convention rules
`JJ`	JJ01	Join rules
`LT`	LT01-LT13	Layout rules
`RF`	RF01-RF06	Reference rules
`ST`	ST01-ST09	Structure rules

Selected sqruff rules¶

Code	Name	Description
`SQ-AL01`	Implicit aliasing	Explicit aliasing with `AS` keyword
`SQ-AL02`	Implicit alias type	Column aliases should be explicit
`SQ-AM01`	Ambiguous DISTINCT	DISTINCT used with both DISTINCT and non-DISTINCT columns
`SQ-CP01`	Keyword capitalization	SQL keywords should be consistently capitalized
`SQ-CP02`	Identifier capitalization	Identifiers should be consistently cased
`SQ-CV02`	COALESCE vs IFNULL/NVL	Prefer COALESCE over vendor-specific functions
`SQ-LT01`	Trailing whitespace	No trailing whitespace
`SQ-LT02`	Indentation	Consistent indentation
`SQ-LT04`	Comma position	Leading or trailing commas consistently
`SQ-LT09`	SELECT targets	Each column on its own line
`SQ-RF02`	Qualified references	References should be qualified in JOINs
`SQ-ST05`	No CTEs	CTEs preferred over subqueries

Sqruff rules are run via scythe lint and scythe fmt. Fixable violations are auto-corrected by scythe fmt.