feat: add demo.sql with 5 impactful SQL checker issues

[sauravsrijan]

Summary

Added a new demonstration file (demo.sql) showcasing 5 of the most impactful SQLFluff violations that are critical in production SQL. This golden test file helps demonstrate the importance of proper SQL linting practices.

Changes

• demo.sql (37 lines): Production-grade SQL examples featuring:

  • AM09: LIMIT without ORDER BY (non-deterministic results)
  • AM05: Unqualified JOINs (ambiguity in multi-table queries)
  • AM08: Implicit cross JOINs (unintended Cartesian products)
  • CP01: Inconsistent keyword capitalization (standards)
  • AL01: Implicit table aliasing (clarity and maintainability)

• test_demo_sql.py (100+ lines): Comprehensive pytest test suite with 9 tests:

  • Individual tests for each of the 5 violations
  • Integration test verifying all 5 issues are present
  • File validation tests (existence, line count, production context)

Test Results

All 9 tests pass:

• ✓ test_am09_limit_without_order_by
• ✓ test_am05_unqualified_join
• ✓ test_am08_implicit_cross_join
• ✓ test_cp01_keyword_capitalization
• ✓ test_al01_implicit_aliasing
• ✓ test_all_five_violations_present
• ✓ test_demo_sql_file_exists
• ✓ test_demo_sql_under_100_lines
• ✓ test_demo_sql_has_production_context

Running `sqlfluff lint demo.sql --dialect postgres` detects all 5 critical violations.

Context

This repository contains golden test files with intentional SQL violations to demonstrate SQLFluff's linting capabilities. The demo.sql file provides realistic, production-level examples that are useful for:

• Demonstrating SQLFluff's core violation detection
• Training developers on common SQL pitfalls
• Validating linter configuration
• Creating comprehensive test coverage for SQL quality assurance

🤖 Generated with Claude Code