# Focus SQL Review > Reviews Focus SQL query builder implementations for correctness and type safety. Use when examining expressions, columns, statements, clauses, SQL generation code, or visitor pattern implementations. Use when this capability is needed. - Skill: `tomevault-io/focus-sql-review` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/focus-sql-review` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/focus-sql-review/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Data & Analytics - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/focus-sql-review --- # Focus SQL Review Review SQL query builder code in the Focus library for correctness, type safety, and API consistency. ## When to Use - Reviewing expression or column implementations - Analyzing statement builders (SELECT, INSERT, UPDATE, DELETE) - Checking clause composition - Validating visitor pattern implementations - Examining SQL generation logic ## Review Checklist ### 1. Type Safety - [ ] Generic types used correctly (e.g., `IntColumn(Int32)` vs `IntColumn(Int64)`) - [ ] Expression hierarchy respected (`IntExpression`, `StringExpression`, `BoolExpression`, `TimeExpression`) - [ ] Column module included properly in column types - [ ] Return types match expected expression types ### 2. Visitor Pattern - [ ] `accept(visitor : SqlVisitor)` implemented correctly - [ ] Corresponding `visit_*` method exists in SqlFormatter - [ ] Inner expressions delegated properly via `.try(&.accept(self))` ### 3. SQL Correctness - [ ] Generated SQL is syntactically valid - [ ] Parameters bound safely (no SQL injection) - [ ] Whitespace handling consistent (trailing space convention) - [ ] Identifier quoting applied when needed ### 4. API Consistency - [ ] Method naming follows Focus conventions (`eq`, `greater_than`, etc.) - [ ] Return type is `BoolExpression` for comparison operations - [ ] Fluent chaining preserved - [ ] Null handling uses `is_null` / `is_not_null` pattern ### 5. Clause Composition - [ ] Clauses implement `ordered_clauses` correctly for statements - [ ] WHERE, HAVING use expression-based conditions - [ ] SET clause handles both values and subqueries ## Key Patterns Reference See [patterns.md](./patterns.md) for detailed type hierarchy and implementation patterns. --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/matthewmcgarvey) — claim your Tome and manage your conversions.