DE//AGENT
Explore
Tutorial Lesson 5 of 10 · The Python & SQL Series community beginner

Fix SQL lint with the SQLFluff core rule pack

Install the SQLFluff core rule pack, point it at your warehouse dialect, and lint a fixture that fails on purpose: indentation, keyword capitalisation, SELECT star, and unused CTEs. You fix each finding while the passing fixture stays green, then wire the same lint run into CI.

At a glance

When Team SQL style drifts and review time burns on formatting; Legacy SQL debt needs fixing incrementally instead of one big reformat
Where SQL
Why Mechanical lint rules settle formatting and naming so review time goes to correctness.

Learning objectives

  • Configure SQLFluff for your warehouse dialect
  • Fix L003, L010, L030, and L057 findings in real SQL
  • Integrate SQLFluff into CI/CD pipelines

What you need

  • Python >= 3.8 with pip
  • pip install sqlfluff==3.0.0 sqlfluff-templater-dbt
  • A .sql file or dbt project to lint

Steps

  1. Configure SQLFluff for your warehouse dialect. (from rule-pack-sqlfluff-core )
  2. L003 — Consistent indentation. (from rule-pack-sqlfluff-core )
  3. L010 — Keywords capitalisation policy (UPPER). (from rule-pack-sqlfluff-core )
  4. L030 — SELECT star usage. (from rule-pack-sqlfluff-core )
  5. L057 — Unused CTE detection. (from rule-pack-sqlfluff-core )
  6. Integrate SQLFluff into CI/CD pipelines. (from rule-pack-sqlfluff-core )

Check yourself

  • sqlfluff lint flags the seeded violations in the failing fixture and returns nothing on the passing one.
  • CI fails on style-severity findings and stays green on the passing fixture.

Worked example

Install SQLFluff 3.0.0 with the dbt templater — from rule-pack-sqlfluff-core 

pip install sqlfluff==3.0.0 sqlfluff-templater-dbt
sqlfluff --version

Set dialect and templater for your project (.sqlfluff) — from rule-pack-sqlfluff-core 

[sqlfluff]
dialect = snowflake   # pack default - set to your warehouse dialect
templater = dbt       # pack default - or jinja for plain SQL

Lint the failing fixture and keep the passing one green — from rule-pack-sqlfluff-core 

sqlfluff lint tests/fixtures/style_fail.sql   # flags the seeded violations
sqlfluff lint tests/fixtures/style_pass.sql   # returns nothing

Sourced from

Security scan

Last sweep 2026-10-24: 0 finding(s), 0 marked as examples.

Common gotchas

  • The pack defaults to the dbt templater and the snowflake dialect — set both to your project or findings mislead.
  • L014 and L030 are warnings, not style errors — severity decides what blocks CI.
  • Fix legacy SQL debt incrementally; a whole-repo reformat buries the real diff.

Production considerations

  • Pin sqlfluff==3.0.0 with sqlfluff-templater-dbt so CI and local runs agree.
  • Exclude rules deliberately via exclude_rules rather than ignoring findings inline.

Diagram

sqlfluff pass
   |
   |- install sqlfluff==3.0.0 + dbt templater
   |
   |- set dialect + templater --> lint fixture
   |
   |- L003 --> L010 --> L030 --> L057 --> fix each finding
   |
   |- lint in CI --> passing fixture stays green

Registry stats

Verification community · Oct 21, 2026
Completeness 81
Trust multiplier ×1.25
Composite 34.15 · adequate
Freshness 3 days since last source check
Difficulty beginner
Version 0.1.0
License CC-BY-4.0
Security flags none